WO2008110110A1 - Ip multimedia subsystem service providing method and system - Google Patents

Abstract

IP multimedia subsystem service (IMS) providing method and system are disclosed. When the other end originates the call, access domain selection function entity (ADSF) receives the call request of the other end, decides the access internet where the user endpoint(UE) receives this call according to the decision parameters pre-stored, and transmits the decision result to the serving call session control function entity (S-CSCF) through the call request, S-CSCF sends the call request to the circuit switched domain adaptor (CSA); the circuit switched (CS) access call branch is established between CSA and UE. When UE originates the call, CS access call branch is established between UE and CSA; the other call branch is established between CSA and the other end, establishing IMS call is finished. Utilizing the method and system disclosed by the solution, access IMS service through CS internet can be realized. And the current CSI service, VCC and ICS service are reformed. Consequently the resource utilization ratio can be increased and the running cost is saved. And it is easy to introduce the new service quickly.

Description

 IP multimedia subsystem service providing method and system

 The present invention relates to IP Multimedia Subsystem (IMS) technology, and more particularly to IMS service provisioning methods and systems. Background of the invention

 At present, mobile communication is mainly based on circuit-switched (CS) networks, such as Global System for Mobile Communications (GSM) and Code Division Multiple Access (CDMA). Operators have established a relatively complete and rich service platform based on CS networks. However, the service provision of the CS network needs to be supported by the roaming mobile switching center (VMSC), which is not conducive to the introduction of new services. The IMS network is an IP-switched service network, which supports user terminals (UEs) to perform IMS multimedia services through various packet-switched access networks, such as IP-access networks (IP-CAN), and its service provision is independent of roaming, which is beneficial to The introduction of new multimedia services.

 However, due to the complexity of the IMS network, it is foreseeable that the deployment of the IMS network will not be completed in a short period of time, that is, the CS network will coexist with the IMS network for a long period of time. In this way, for each new service, operators need to create two business platforms. Undoubtedly, the result is increased construction costs and operating costs. Therefore, in terms of reducing costs or facilitating the smooth evolution of the CS network to the IMS network, it is necessary to study the technology of UEs to IMS services through CS.

The multimedia telephony service in the IMS service supports supplementary services in the CS network, such as call hold, call forwarding, conference calls, etc., and its supplementary service features are provided by the Telephony Application Server (TAS). In view of the limited deployment of IP voice access networks currently supporting Voice over IP (VoIP), a technology for combining circuit switched and IMS services (CSI) has been developed in the prior art. That is, the UE carries real-time voice and real-time video media through the CS network, and carries other non-real-time media, such as file transmission and instant messaging, through the IP access network. The CSI service is an end-to-end service that usually does not require the support of a dedicated server on the network side. The CSI-UE may also receive other calls of the IMS-UE that do not support the CSI service. At this time, the server may make an access network decision for the call. If the CS and the IP access network are required to be used simultaneously, the call needs to be split. The real-time media is sent to the UE through the CS network (the server and the UE are required to establish a CS access call leg to carry the real-time media), and the non-real-time media is sent to the UE through the IP access network. If the IMS-UE supports the CSI service, the multimedia service, such as a multimedia conference call, can be carried out by means of the CS network even if the IMS-UE is in an IP access network that does not support VoIP.

 The voice call continuity (VCC) service in the prior art is suitable for a user to move from a CS network to an IP access network, and also supports switching from a CS call to a VoIP call, and neither user feels the handover process occurs. . The VCC service was originally developed for CS voice calls, and is also applicable to CS videophone (VP) calls, but needs to solve the interworking problem between CS network VP control protocol and Session Initiation Protocol (SIP). Currently, there is corresponding standardization research. The VCC service needs to be supported by the IMS server, including receiving a call sent by the UE through the CS network, making an access network decision for the incoming call, and delivering the call to the UE through the CS network (requires the server and the UE to establish a CS access call branch) The way to carry the real-time media), as well as providing a handover control point, switches the old access call leg with the new access call leg, while the call legs of the server and the peer user remain unchanged.

In addition to CSI and VCC, an IMS Concentrated Service (ICS) is also being studied in the prior art. The ICS service provides the ability for the UE to use the CS network as the access network to connect to the IMS network. The CS network only retains basic switching and control functions, and the main service control is implemented in the IMS network. In this way, operators use IMS as a unified service platform, which greatly reduces the construction cost and operating cost of new services. Due to the presence of the UE using different access networks to receive incoming calls Possibly, therefore, the ICS server needs to make access network decisions.

 Although the above three services are currently implemented by independent servers, there are obvious duplications in functions, mainly reflected in: access network decision and CS access call branch establishment. This will result in lower resource utilization and increased operating costs, and will not be conducive to rapid entry into new services. Summary of the invention

 The embodiments of the present invention provide an IMS service providing method and system, which can improve resource utilization and save operating costs, and facilitate the rapid introduction of new services.

 An embodiment of the present invention provides an IMS service providing method, where the method includes:

 The access domain selection function entity ADSF receives the call request of the peer end sent by the call session control function entity S-CSCF, and the decision user terminal UE receives the access network of the current call, and sends the decision result to the S-CSCF through the call request. ;

 The S-CSCF sends a call request to the circuit switched domain adapter CSA according to the decision result;

 A circuit-switched CS access call leg is established between the CSA and the UE, and the IMS service is received by the CS access call leg.

 An embodiment of the present invention provides an IMS service providing method, where the method includes:

 The CSA receives a call request from the UE, and the call request request performs an IMS service with the opposite end;

 Establishing a CS access call leg with the UE according to the call request; and establishing another call leg with the peer end, and receiving the IMS service by using the call leg.

 An embodiment of the present invention provides an IMS service providing system, where the system includes:

 An S-CSCF, configured to receive a call request from a peer end and send the call request;

ADSF, configured to receive a call request from a peer sent by the S-CSCF, according to pre-stored The decision parameter decision UE receives the access network of the current call, and sends the decision result by using a call request;

 The S-CSCF is further configured to receive a call request carrying a decision result from the ADSF, and send a call request according to the decision result;

 The CSA is configured to receive a call request sent by the S-CSCF according to the decision result, establish a CS access call leg with the UE, and receive an IMS service by using the CS access call leg.

 An embodiment of the present invention provides an IMS service providing system, where the system includes:

 The CSA is configured to receive a request for sending the UE and a call request for the IMS service by the opposite end, establish a CS access call leg with the UE, and establish another call leg with the peer end, by using the call leg Receive IMS services.

 An embodiment of the present invention provides an IMS service providing method, where the method includes: receiving a call request sent by a peer end, and sending the call request to an ADSF decision UE to receive an access network of the current call;

 Receiving a decision result from the ADSF;

 Sending a call request to the CSA according to the decision result, so that the CSA establishes a CS access call leg with the UE, so that the UE receives the IMS service through the CS access call leg.

It can be seen that, in the technical solution of the embodiment of the present invention, the IMS service, such as the multimedia telephony service, the CSI service, the VCC service, and the like, is received through the CS network by providing a reasonable architecture; The CSI service, VCC, and ICS services have been reorganized to integrate the functions of each solution in the prior art, thereby improving resource utilization and operating cost, and facilitating the rapid introduction of new services. BRIEF DESCRIPTION OF THE DRAWINGS

 The above and other features and advantages of the present invention will become more apparent to those skilled in the <

 1 is a flowchart of a specific implementation manner of a method for receiving a call in an IMS service providing mode according to the present invention;

 2 is a flowchart of a specific implementation manner of a method for initiating a call and implementing a VCC handover in an IMS service providing mode according to the present invention;

 FIG. 3 is a first embodiment of a method for receiving a call in an IMS service providing mode according to the present invention; FIG. 4 is a schematic diagram of a method for initiating a call in an IMS service providing mode according to the present invention; Method of switching one embodiment;

 FIG. 6 is another embodiment of a method for receiving a call in an IMS service providing mode according to the present invention; FIG. 7 is another embodiment of a method for initiating a call in an IMS service providing mode according to the present invention; Another embodiment of a method for implementing VCC switching;

 9 is a schematic diagram of a specific implementation manner of a system when receiving a call in an IMS service providing mode according to the present invention;

 10 is a schematic diagram of a specific implementation manner of a system for initiating a call and implementing VCC handover in an IMS service providing mode according to the present invention;

 FIG. 11 is a schematic structural diagram of another embodiment of an IMS service providing system according to the present invention; FIG. 12 is a schematic structural diagram of another embodiment of an IMS service providing system according to the present invention; Mode for carrying out the invention

In order to make the objects, technical solutions and advantages of the present invention more clear, the following reference is made to the accompanying drawings. The invention will be further described in detail by way of examples.

 In an embodiment of the present invention, a Circuit Switched Domain Adapter (CSA) provides a network adaptation function to implement an IMS service that carries/provides media such as voice or video telephony (VP) using a CS network. In a specific embodiment of the present invention, a specific embodiment when receiving a call, initiating a call, and implementing VCC handover by using the IMS service providing method of the present invention is provided.

 FIG. 1 is a flowchart of a specific implementation manner of a method for receiving a call in an IMS service providing mode according to the present invention. As shown in Figure 1, the following steps are included:

 Step 101: The access domain selection function entity (ADSF) receives the call request of the opposite end, determines, according to the pre-stored decision parameter, the UE receives the access network of the current call, and sends the decision result to the monthly service call session control through the call request. Functional entity (S-CSCF), the S-CSCF sends a call request to the CSA.

 Before the step, the method further includes: the S-CSCF receives the call request of the peer end, and sends the call request to the TAS according to the initial filtering rule (iFC) check, and after receiving the call request, the TAS performs the service logic processing, and performs the service logic, and - The CSCF returns a call request. If the user subscribes to the voice call continuous (VCC) service, the S-CSCF will further send the call request to the call continuity function entity (CCF) according to the iFC check of the VCC service; after the CCF receives the call request, whether the decision is subsequently VCC handover supporting the call: If supported, terminate the call request conversation, create a new conversation, and send a call request to the S-CSCF through the new dialog; otherwise, directly send a call request to the S-CSCF, the call is Subsequent requests will no longer pass through the CCF. The dialog mentioned here refers to the call relationship between the functional entity user agents (UAs, User Agents) in the SIP protocol.

Thereafter, the S-CSCF sends the call request to the ADSF, and the ADSF determines, according to the decision parameter, the access network that the UE receives the call, such as a CS network or a packet switched (PS) network, or a CS network and a PS network. If the decision result is a CS network, the S-CSCF sends a call request to the CSA; if the decision result is a PS network, the S-CSCF sends a call request to P-CSCF; If the decision result is a CS network and a PS network, the S-CSCF simultaneously sends two call requests to the CSA and the P-CSCF, respectively.

 The decision parameters mentioned here include the access network used by the current UE in progress, the registration information of the CS and the IMS, the operator policy, the user preference, the UE capability, and/or the access network capability of the UE. These parameters are stored by the ADSF when it interacts with other functional entities in the network and the UE. The ADSF sends the decision result to the S-CSCF through the call request, and the S-CSCF sends a call request to the CSA: The S-CSCF sends the call request to the CSA according to the iFC check; or, the S-CSCF controls the functional entity through the proxy call session (P- CSCF) sends a call request to the CSA.

 Step 102: Establish a CS access call leg between the CSA and the UE, and complete an IMS call setup.

 In this step, after receiving the call request of the incoming call, the CS A establishes a CS access call branch with the UE, and the establishment process is different according to the different IMS service delivery modes adopted:

 Manner 1: The CSA terminates the call requesting session, creates a new session, and sends a call request to the S-CSCF through the new session. The call request carries the IP media routing number assigned by the peer media request and the CSA for the call. (IMRN); The S-CSCF sends the call request to the UE; the UE establishes a CS call with the CSA through the IMRN.

 Manner 2: After receiving the call request sent by the S-CSCF, the CSA terminates the session of the call request and sends a call request to the UE through the CS network. Specifically, the CSA sends the peer media request to the UE through the unstructured supplementary service data (USSD) message and the IMRN allocated by the CSA for the call; the UE initiates a CS call to the CSA through the IMRN.

Mode 3: Basically the same as Mode 2, the only difference is that the message transmitted between the CSA and the S-CSCF needs to pass through a P-CSCF, and the S-CSCF is checked at all iFCs. After completion, instead of sending a call request to the CSA based on the iFC check.

 2 is a flow chart of a specific implementation manner of a method for initiating a call and implementing VCC handover in an IMS service providing mode according to the present invention. As shown in Figure 2, the following steps are included:

 Step 201: The UE sends a call request to the CSA, and the UE establishes a CS access call leg between the UE and the CSA.

 Initiating a call for a UE:

 The specific process for establishing a CS access call leg between the UE and the CSA is different according to the different IMS service delivery modes used in this step:

 Manner 1: The UE sends a call request to the peer end to the S-CSCF through the PS access network, where the call request carries the real-time media to carry the request through the CS network, such as an IMRN request; and the S-CSCF sends the call request according to the iFC check. To the CSA, the CSA terminates the session of the call request, and returns a temporary response message to the S-CSCF, where the temporary response message carries the IMRN; the S-CSCF sends the temporary response message carrying the IMRN to the UE, and the UE initiates through the IMRN. CS call to CSA.

 Manner 2: The UE sends a call request to the CSA through the CS network, where the call request carries a peer address and a real-time media request. The call request may be sent through the USSD message, and the non-real time media request may be further carried in the call request, and the non-real time media will be carried by the USSD message.

 Manner 3: Basically the same as Mode 2, the only difference is that the message transmitted between the CSA and the S-CSCF needs to pass through a P-CSCF.

 For VCC switching:

 The specific process for establishing a CS access call leg between the UE and the CSA is different according to the different IMS service delivery modes used in this step:

Manner 1: The UE sends a call request to the CCF to the S-CSCF, where the call request carries a real-time media bearer request through the CS network, such as an IMRN request; the S-CSCF is configured according to The iFC checks the call request to the CSA, the CSA terminates the session of the call request, and returns a temporary response message to the S-CSCF, where the temporary response message carries the IMRN; the S-CSCF sends the temporary response message carrying the IMRN To the UE, the UE establishes a CS call to the CSA through the IMRN.

 Manner 2: The UE sends a call request to the CSA through the USSD message. The CCF carries the CCF call address. The CSA sends the IMRN to the UE through the USSD message. The UE establishes a CS call with the CSA through the IMRN.

 Manner 3: Basically the same as Mode 2, the only difference is that the message transmitted between the CSA and the S-CSCF needs to pass through a P-CSCF.

 Step 202: The CSA establishes another call leg with the peer to complete the IMS call setup. Initiating a call for a UE:

 The CSA generates a call request to the peer and sends the call request to the S-CSCF, and the S-CSCF sends the call request to the peer.

 Before the S-CSCF sends the call request to the peer, it may further include: If the user signs the VCC service, the B' J S-CSCF checks the iFC check ^! The call request is sent to the CCF, and the CCF decides whether to support the VCC handover of the call: if supported, the session of the call request is terminated, a new session is created, and a call request is sent to the S-CSCF through the new dialog; , directly return the call request to the S-CSCF, subsequent requests for this call will no longer pass the CCF. Thereafter, the S-CSCF can also send a call request to the TAS for service logic processing according to the iFC check, and accordingly, the TAS returns a call request to the S-CSCF.

 For VCC switching:

The CSA generates a call request to the CCF and sends it to the S-CSCF; the S-CSCF sends a call request to the CCF according to the request URI of the call request; the CCF decides, according to the request URI, that the call request is a VCC handover request, The S-CSCF sends a session modification message; the S-CSCF sends the session modification message to the peer end, and the peer end sends back to the S-CSCF for the session. Modify the response message of the message; the S-CSCF sends the response message to the CSA.

 The method of the present invention will be further described in detail below through specific embodiments. FIG. 3 is a schematic diagram of an embodiment of a method for receiving a call in an IMS service providing mode according to the present invention. As shown in Figure 3, the following steps are included:

 Step 301: The S-CSCF receives the call request (Invite) sent by the peer end, and sends the Invite message to the TAS according to the iFC check. After the TAS performs the service logic processing, the TSS sends the Invite message to the S-CSCF.

 The Invite message can carry voice, VP, and other non-real-time media requests, such as instant messaging.

 Step 302: If the user subscribes to the VCC service, the S-CSCF sends an Invite message to the CCF according to the iFC check of the VCC service, and the CCF decides whether to support the VCC switch of the Invite message: If yes, the session of the Invite message is suspended ( Dialog ) -1 , generate a new Dialog-2, and send the Invite message to the S-CSCF through the newly generated Dialog-2; otherwise, the CCF will send the Invite message back to the S-CSCF, and the request message in the subsequent process will not Then pass the CCF.

 Steps 301 ~ 302 are optional steps.

Step 303: The S-CSCF sends an Invite message to the ADSF according to the iFC check. The ADSF determines, according to the decision parameter, the UE receives the access network of the call, and returns an i _nv i _te message carrying the access network selection information to the S- CSCF.

 The decision parameters include: the access network where the current UE is currently calling, the registration information of the CS and the IMS, the operator policy, the UE preference, the UE capability, and the capability of the UE to access the network.

The access network that the UE receives the call may be a CS network or a PS network. The CS and the PS network may also be used at the same time. In this case, the IMS call established by the UE carries the real-time voice or VP media through the CS network. Can carry other devices through the PS network at the same time Non-real time media, such as file transfers. In this embodiment, it is assumed that the ADSF decision uses both the CS and the PS network. Access network selection information can be passed through extended SIP header or header parameters or as extended SDP information. For example, To:called-example@huawei.com; access-type=CSnPS.

 Step 304: The S-CSCF sends an Invite message to the CSA according to the iFC (including the access network parameter condition). After receiving the Invite message, the CSA aborts the Dialog-2 of the Invite message, generates Dialog-3, and sends the Invite message. Go to the S-CSCF.

 The Invite message described in this step carries the media request of the peer and the IMRN allocated by the CSA for the call. For example, IMRN can be used as the contact header content, contact: 87654321.

 Step 305: The S-CSCF sends an Invite message to the UE through the P-CSCF, where the Invite message carries the IMRN and the peer media request.

 Steps 306 ~ 307: The UE initiates a CS call through the IMRN, and the CS call is sent to the MGCF through the VMSC. After receiving the CS call, the MGCF generates a SIP Invite message and sends the Invite message to the CSA. In the process, MGCF generates Dialog-4.

 So far, a CS access call leg is established between the CSA and the UE.

 Steps 308 ~ 309: The UE generates a 200 OK message, and sends the 200 OK message to the CSA through the P-CSCF and the S-CSCF.

 The 200 OK message carries a response of the UE to the peer media request, such as accepting or rejecting.

 Step 310: The CSA generates a 200 OK message, which is sent to the S-CSCF as a final response to the Invite message in Dialog-2.

 The 200 OK message carries a response of the UE to the peer media request.

Step 311: The S-CSCF sends a 200 OK message to the ADSF; the ADSF sends a 200 OK message to the S-CSCF. Step 312: The S-CSCF sends a 200 OK message to the CCF; the CCF sends a 200 OK message to the S-CSCF through the Dialog-1.

 Step 313: The S-CSCF sends a 200 OK message to the TAS. The TAS sends a 200 OK message to the S-CSCF and sends it to the peer.

 Steps 314 ~ 316: The peer sends an Ack message to the S-CSCF; the S-CSCF sends the Ack message to the TAS; the TAS sends an Ack message to the S-CSCF; after that, if the CCF supports the VCC switch, the B' J S-CSCF Ack The message, send ^ ij CCF, and send it to the CSA after the Ack message returned by ^ j CCF; otherwise, the S-CSCF directly sends the Ack message to the CSA.

 Steps 317 ~ 319: The CSA generates a 200 OK message and sends it to the MGCF. The MGCF sends a 200 OK message to the VMSC. The VMSC generates a Connect message and sends it to the UE, indicating that the UE CS call is successfully established. The MGCF sends an Ack message to the CSA. .

 Steps 320 ~ 321: The CSA sends an Ack message to the UE through the S-CSCF and the P-CSCF. The CSA sends an Ack message to the UE through the Dialog-3.

 FIG. 4 is a schematic diagram of an embodiment of a method for initiating a call in an IMS service providing mode according to the present invention. As shown in Figure 4, the following steps are included:

 Steps 401 ~ 404: The UE sends an Invite message to the S-CSCF through the P-CSCF, where the Invite message carries voice, VP, and/or other non-real-time media requests, and real-time media requests through the CS network, such as IMRN requests. To:calling-example@huawei.com; IMRN=? The S-CSCF sends an Invite message to the CSA according to the iFC check;

After receiving the Invite message, the CSA aborts the Dialog-1 of the Invite message, and returns a temporary response message carrying the IMRN to the S-CSCF, for example, the IMRN as the contact header content, contact: 12345678, such as 183 message; The CSCF sends the 183 message to the UE through the P-CSCF. The iFC carries the CS network bearer request parameter condition.

 Steps 405 - 406: The UE initiates a CS call (voice or VP) through the IMRN, and the CS call is sent to the MGCF through the VMSC; the MGCF generates a SIP Invite message and sends it to the CSA, and the CSA terminates the Dialog-2 of the Invite message.

 Through steps 401 ~ 406, a CS access call leg is established between the UE and the CSA. Step 407: The CSA generates an Invite message (voice or VP, and/or other non-real time media request), sends it to the S-CSCF, and creates a Dialog-3 accordingly.

 Step 408: If the user subscribes to the VCC service, the S-CSCF sends an Invite message to the CCF according to the iFC check, and the CCF decides whether to support the VCC switch for the call: If supported, the session of the Invite message is aborted, and a Dialog is generated. -4, and send the Invite message to the S-CSCF; otherwise, the CCF returns the Invite message to the S-CSCF, and the Invite message in the subsequent process will no longer pass the CCF.

 Step 409: The S-CSCF sends an Invite message to the TAS according to the iFC, and the TAS performs related service logic processing, and returns the Invite message to the S-CSCF. The S-CSCF sends the Invite message to the peer end.

 Steps 408 ~ 409 are optional steps.

 Step 410: The peer returns a 200 OK message carrying a response to the UE media request to the S-CSCF.

 Step 411: The S-CSCF sends a 200 OK message to the TAS and the CCF, and the TAS and the CCF respectively return a 200 OK message to the S-CSCF.

 Step 412: The S-CSCF sends a 200 OK message to the CSA.

 Steps 413 ~ 415: The CSA sends a 200 OK message to the MGCF; the MGCF sends a 200 OK message to the VMSC; the VMSC generates a Connect message, and sends the Connect message to the UE, indicating that the CS call is successfully established; and the MGCF sends an Ack message to the CSA.

Steps 416~419: The CSA sends a 200 OK message to the S-CSCF through Dialog-1. The 200 OK message is sent to the UE through the P-CSCF; the UE returns an Ack message to the CSA through the S-CSCF.

 Steps 420 ~ 422: The CSA sends an Ack message to the peer through Dialog-3.

 FIG. 5 is a schematic diagram of an embodiment of a method for implementing VCC handover in an IMS service providing mode according to the present invention. In this embodiment, it is assumed that the UE switches the call from the WLAN to the UMTS network (in the UTMS network, the UE can simultaneously access the CS and the PS network in parallel), and it is assumed that the UE has established an IMS through a PS access network and the peer. Session, the session includes voice, VP, and/or other non-real-time media; the CCF exists as a handover control point in the signaling path, and the CCF and the UE establish Dialog-1, and the peer establishes Dialog-2. In summary, this embodiment reuses the call initiation process of mode 1, and the called party is CCF. After the handover is successful, the CCF will release Dialog-1 with the UE. As shown in FIG. 5, the embodiment includes the following steps: Steps 501 to 504: The UE sends an Invite message to the CCF through the (P-CSCF) 2 to the S-CSCF, where the Invite message carries voice or VP, and / Or other non-real-time media requests, as well as requests to host real-time media over the CS network, such as IMRN requests, To: calling-example @ huawei .com; IMRN=? The S-CSCF sends the Invite message to the CSA according to the iFC;

 After receiving the Invite message, the CSA aborts the Dialog-3 of the Invite message, and returns a temporary response message carrying the IMRN identifier to the S-CSCF, for example, the IMRN as the contact header content, contact: 23456789, such as 183 message; The S-CSCF sends the 183 message to the UE through the P-CSCF2.

 Steps 505 - 506: The UE initiates a CS call (voice or VP) through the IMRN, and the CS call sends the MGCF through the VMSC; the MGCF generates a SIP Invite message (voice or VP) and sends it to the CSA, and the CSA aborts the Dialog of the Invite message. 4.

Step 507: The CSA generates an Invite message to the CCF and sends it to the S-CSCF. The Invite message is a call of the UE to the PSI, and the S-CSCF is responsible for routing. Correspondingly, CSA creates a Dialog-5.

 Steps 508 ~ 509: The S-CSCF sends an Invite message to the CCF according to the Invite request URI, and the CCF decides according to the Invite request URI that this is a VCC handover request; CCF aborts Dialog-5, and passes Dialog-2 to the S-CSCF. Sending a session modification message, such as a re-invite message (Re-Invite message) or an update (Update), etc.; the S-CSCF sends the session modification message to the TAS; the TAS returns the session modification message to the S-CSCF, and modifies the session The message is sent to the peer.

 Step 510: The peer returns a response 200 OK message to the S-CSCF for the session modification message.

 Step 511: The S-CSCF sends a 200 OK message to the TAS and the CCF, and the TAS and the CCF respectively return a 200 OK message to the S-CSCF.

 Step 512: The S-CSCF sends a 200 OK message to the CSA.

 Steps 513 ~ 515: The CSA sends a 200 OK message to the MGCF; the MGCF sends a 200 OK message to the VMSC; the VMSC generates a Connect message, and sends the Connect message to the UE, indicating that the UE, the CS call is successfully established; and the MGCF sends an Ack message to the CSA.

 Steps 516~519: The CSA sends a 200 OK message to the S-CSCF through the Dialog-3, and then sends the 200 OK message to the UE through the P-CSCF2. The UE returns an Ack message to the CSA through the S-CSCF.

 Steps 520 - 522: If the CSA uses the re-Invite message for session modification, it needs to send an Ack message to the peer through Dialog-2.

 Steps 523 ~ 525: CCF releases Dialog-1 between the UE and the UE.

 The three embodiments described above are used to implement the IMS service access process by the UE in the first mode. The following describes the process of the UE using the second mode to implement the IMS service access.

6 is another implementation of a method for receiving a call in an IMS service providing mode according to the present invention example. As shown in Figure 6, the following steps are included:

 Steps 601 ~ 603: The same as steps 301 ~ 303, and will not be described again.

 Steps 604 ~ 605: The S-CSCF sends an Invite message to the CSA according to the iFC check, the CSA aborts the dialog Dialog-2 of the Invite message, and sends the media request of the peer and the IMRN to the UE through the USSD message (optional).

 The iFC carries the access network type selection parameter. The USSD message is sent from the CSA to the UE through the HSS/VLR/VMSC, the VLR/VMSC or the VMSC. In this embodiment, it is assumed to be sent by the three network elements of the HSS/VLR/VMSC.

 Steps 606 ~ 607: The UE initiates a CS call through the IMRN, and the CS call is sent to the MGCF through the VMSC. After receiving the CS call, the MGCF generates a SIP Invite message, and sends the Invite message to the CSA, and the CSA generates a Dialog- correspondingly. 3.

 Through steps 604 ~ 607, a CS access call leg is established between the CSA and the UE.

 Steps 608 - 617: The same as steps 310 - 319, and will not be described again.

 According to the above steps, the UE can carry voice or VP through the CS, and can also carry other non-real-time media such as instant messaging and file transmission through the USSD, or even not to establish a CS bearer.

 FIG. 7 is another embodiment of a method for initiating a call in an IMS service providing mode according to the present invention. As shown in Figure 7, the following steps are included:

 Step 701: The UE sends a peer call address to the CSA through the USSD request message, and the message arrives at the CSA through the VMSC/VLR/HSS, the VMSC/VLR, or the VMSC. In this embodiment, it is assumed that the three network elements are sent to the VMSC/VLR/HSS. CSA.

 The USSD request message may include an instant message or a text media request.

 Step 702: The CSA sends the IMRN identifier to the UE by using the USSD message.

Steps 703 - 704: The UE initiates a CS call (voice or VP) through the IMRN, the CS The call sends the MGCF through the VMSC; the MGCF generates a SIP Invite message and sends it to the CSA, which terminates the Dialog-1 of the Invite message.

 Step 705: The CSA generates an Invite message (voice or VP, and/or message and text media) to the peer, and sends it to the S-CSCF. Accordingly, the CSA creates a Dialog-2.

 Step 706: If the user subscribes to the VCC service, the BJS-CSCF sends an Invite message to the CCF according to the iFC, and the CCF decides whether to support the VCC handover for the call: If supported, the session of the Invite message is aborted, and a Dialog is generated. -3, and send the Invite message to the S-CSCF; otherwise, the CCF returns the Invite message to the S-CSCF, and the Invite message in the subsequent process will no longer pass the CCF.

 Steps 707 - 713: Same as steps 409 - 415, no longer mentioned.

 Steps 714 ~ 716: The CSA sends an Ack message to the peer through Dialog-2.

 FIG. 8 is another embodiment of a method for implementing VCC handover in an IMS service providing mode according to the present invention. In this embodiment, it is assumed that the UE switches the call from the WLAN to the GSM network, and it is assumed that the UE has established an IMS session with the peer through a PS access network, the session includes voice or VP, and other non-real-time media; CCF As a handover control point exists in the signaling path, and the CCF and the UE establish Dialog-1, and the opposite end establishes Dialog-2. In summary, this embodiment adopts the call initiation process of mode 2, and the calling party is CCF. After the handover is successful, the CCF will release Dialog-1 between the UE and the UE. As shown in Figure 8, this embodiment includes the following steps:

 Step 801: The UE sends a CCF call address to the CSA through the USSD message, and the message is sent to the CSA through the VMSC/VLR/HSS, the VMSC/VLR, or the VMSC. In this embodiment, the UE sends the CSC to the CSA through the VMSC/VLR/HSS.

 Step 802: The CSA sends the IMRN identifier to the UE by using the USSD message.

Steps 803 to 804: The UE initiates a CS call through the IMRN, and the CS call sends the MGCF through the VMSC. The MGCF generates a SIP Invite message and sends it to the CSA, CSA. Stop the Dialog-3 of the Invite message.

 Step 805: The CSA generates an Invite message to the CCF and sends it to the S-CSCF. Accordingly, the CSA creates a Dialog-4.

 Steps 806 ~ 807: The S-CSCF sends an Invite message to the CCF according to the URI of the Invite message, and the CCF decides according to the URI of the Invite message that this is a VCC handover request; CCF aborts the Dialog-4, and passes the Dialog-2 to the S-CSCF. Sending a session modification message, such as a re-Invite message; the S-CSCF sends the session modification message to the TAS; the TAS returns the session modification message to the S-CSCF, and sends the session modification message to the peer end.

 Steps 808 - 813: The same as steps 510 - 515, and will not be described again.

 Steps 814~816: The CSA sends an Ack message to the peer through Dialog-4.

 Steps 817 ~ 820: The CCF releases Dialog-1 between it and the UE.

 The implementations of the foregoing embodiment are the implementation process of the UE accessing the IMS service in the mode 1 and the implementation process of the UE accessing the IMS service in the mode 2, and the implementation process of the UE using the mode 3 accessing the IMS service is basically the same as the mode 2, The only difference is that the message transmitted between the CSA and the S-CSCF needs to be forwarded through a P-CSCF, and the S-CSCF checks all the iFCs, instead of sending the call request to the CSA according to the iFC check. No longer.

 Based on the above method, FIG. 9 is a schematic diagram of a specific implementation manner of a system for receiving a call in the IMS service providing mode according to the present invention. As shown in FIG. 9, the system includes at least: an S-CSCF, an ADSF, and a CSA. among them:

 The ADSF is configured to receive a call request of the peer end sent by the S-CSCF, and determine, according to the pre-stored decision parameter, the UE to receive the access network of the call, and send the decision result by using the call request;

An S-CSCF, configured to receive a call request from the opposite end and send the call request of the opposite end to the ADSF, and receive a call request from the ADSF carrying the decision result, according to the The decision result sends a call request;

 The CSA is configured to receive a call request from the S-CSCF, establish a CS access call leg with the UE, and receive the IMS service through the CS access call leg.

 In addition, the system further includes an MGCF, configured to receive a CS call initiated by the UE during the establishment of the CS access call leg by the CSA and the UE, and generate a SIP call request according to the CS call, and send the call to the CSA; the CSA generates a new one. The call is requested and sent to the S-CSCF.

 The system further includes a TAS, configured to receive a peer call request sent by the S-CSCF, perform service logic processing according to the call request, and send a call request to the S-CSCF.

 The system further includes a CCF, configured to receive a call request from the S-CSCF, and decide whether to support the VCC handover of the call subsequently, if supported, terminate the conversation of the call request, and create a new conversation, through a new conversation The S-CSCF sends a call request; otherwise, the call request is directly returned to the S-CSCF.

 FIG. 10 is a schematic diagram of a specific implementation manner of a system for initiating a call and implementing VCC handover in an IMS service providing mode according to the present invention. As shown in Figure 10, the system includes a CSA and further includes an S-CSCF.

 The CSA is configured to receive a request sent by the UE and perform a call request for the IMS service by the peer end, establish a CS access call leg with the UE, and establish another call leg with the peer end;

The S-CSCF is configured to receive a call request from the CSA and send the call request to the peer.

 The system further includes an MGCF, configured to receive a CS call initiated by the UE during the establishment of the CS access call leg by the UE and the CSA, and generate a SIP call request according to the CS call to send to the CSA; the CSA generates a new call. Request and send to the S-CSCF.

The system further includes a CCF, configured to receive a call request sent by the S-CSCF, and decide whether to support the VCC handover of the call subsequently, if supported, terminate the conversation of the call request, and create a new conversation, through a new conversation. Send a call request to the S-CSCF; otherwise, The call request is directly sent back to the S-CSCF; or, the CCF is configured to receive a call request from the S-CSCF, and send a session modification message to the S-CSCF when the decision-to-call request is a VCC handover request; the S-CSCF further And sending, by the CCF, a session modification message to the peer, and receiving a response message sent by the peer for the session modification message to the CSA. This role of the CCF will be used to implement VCC switching.

 The system further includes a TAS, configured to receive a call request sent by the S-CSCF, perform service logic processing according to the call request, and send a call request to the S-CSCF.

 The units introduced in the above two system embodiments are only the main units for achieving the object of the present invention. In practical applications, functional units such as P-CSCF, HSS, and VMSC may be added to the above two system embodiments according to actual needs. Those skilled in the art will be able to more readily understand the manner in which these functional units are connected in the system and their functions in accordance with the present disclosure.

 Figures 11, 12 and 13 are schematic views of the structure of an embodiment of the IMS service providing system of the present invention, respectively. The workflow of the system embodiment shown in FIG. 11 corresponds to the method embodiments of FIG. 3, FIG. 4 and FIG. 5, and the workflow of the system embodiment shown in FIG. 12 corresponds to the method embodiments of FIG. 6, FIG. 7, and FIG. The workflow of the system embodiment shown in FIG. 13 is different from the system embodiment shown in FIG. 12 in that: the message transmitted between the CSA and the S-CSCF needs to be forwarded by the P-CSCF, and the S-CSCF is in the All iFC checks are completed, instead of sending a call request to the CSA based on the iFC check. The specific working procedures of the system embodiments shown in FIG. 11, 12, and 13 are respectively referred to the corresponding descriptions in the method embodiments, and are not described herein again.

 It can be seen that, by adopting the technical solution of the embodiment of the present invention, the IMS service is accessed through the CS network, and the solution of the present invention reorganizes the ICS service, the CSI service, and the VCC service in the prior art, and integrates the prior art. The functions of each solution can improve resource utilization and save operating costs, and facilitate the rapid introduction of new services.

In summary, the above is only a preferred embodiment of the present invention, and is not intended to limit the present invention. The scope of protection. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and scope of the present invention are intended to be included within the scope of the present invention.

Claims

Claim  An IMS service providing method, the method comprising:  The access domain selection function entity ADSF receives the call request of the peer end sent by the call session control function entity S-CSCF, and the decision user terminal UE receives the access network of the current call, and sends the decision result to the S-CSCF through the call request. ;  The S-CSCF sends a call request to the circuit switched domain adapter CSA according to the decision result;  A circuit-switched CS access call leg is established between the CSA and the UE, and the IMS service is received by the CS access call leg.  The method according to claim 1, wherein the determining, by the determining UE, the access network of the current call comprises: determining, according to the pre-stored decision parameter, the UE receiving the access network of the current call;  The decision parameters include: an access network used by the current UE in progress, a registration information of the CS and the IMS, an operator policy, a user preference, a UE capability, and one or any of the access network capabilities of the UE. combination.  The method according to claim 2, wherein the decision result is: a CS network, or a packet switched PS network, or a CS network and a PS network.  The method according to claim 1, wherein before the receiving, by the ADSF, the call request of the peer sent by the S-CSCF, the method further includes:  The S-CSCF receives the call request of the opposite end, and sends the call request to the ADSF according to an initial filtering rule iFC check.  The method according to claim 1, wherein the sending, by the S-CSCF, a call request to the CSA according to the decision result includes:  The S-CSCF sends the call request to the CSA according to the iFC check; Alternatively, the S-CSCF passes the proxy call session control function entity P-CSCF The call request is sent to the CSA.  The method according to claim 1, wherein the establishing an CS access call leg between the CSA and the UE comprises:  After receiving the call request sent by the S-CSCF, the CSA terminates the session of the call request, creates a new session, and sends a call request to the UE through the S-CSCF by using the new session, where the call request carries a pair The end media request and the IP multimedia routing number IMRN allocated by the CSA for the call, so that the UE establishes a CS access call leg through the IMRN and the CSA.  The method according to claim 1, wherein the establishing an CS access call leg between the CSA and the UE comprises:  After receiving the call request sent by the S-CSCF, the CSA terminates the call requesting session, and sends a call request to the UE through the CS network to complete the establishment of the CS access call leg.  The method according to claim 7, wherein the sending, by the CSA, a call request to the UE by using a CS network includes:  The CSA sends a call request to the UE through the unstructured supplementary service data USSD message.  The method according to claim 8, wherein the call request message carries a media request and an IMRN; and the UE initiates a CS call to the CSA through the IMRN.  The method according to claim 4, wherein the S-CSCF receives the call request of the opposite end, and before sending the call request to the ADSF according to the iFC check, the method further includes: The S-CSCF sends the call request to the telephony application server TAS for service logic processing according to the iFC check, and the TAS returns a call request to the S-CSCF. The method according to claim 4, wherein the S-CSCF receives the call request of the peer end, and before sending the call request to the ADSF according to the iFC check, the method further includes:  The S-CSCF sends the call request to the call continuity function entity CCF according to the iFC check;  Whether the CCF decision subsequently supports the VCC handover of the call: if supported, terminating the conversation of the call request, creating a new conversation, and sending a call request to the S-CSCF through the new dialog; otherwise, the CCF is directly A call request is returned to the S-CSCF, and subsequent requests for this call will no longer pass through the CCF.  12. An IMS service providing method, the method comprising:  The CSA receives a call request from the UE, and the call request request performs an IMS service with the opposite end;  Establishing a CS access call leg with the UE according to the call request; and establishing another call leg with the peer end, and receiving the IMS service by using the call leg.  The method according to claim 12, wherein the establishing the CS access call leg with the UE comprises:  The UE sends a call request to the peer end to the S-CSCF through the P-CSCF, where the call request carries the real-time media through the CS network to carry the request;  The S-CSCF sends the call request to the CSA according to the iFC check, the CSA terminates the session of the call request, and returns a temporary response message to the S-CSCF, where the temporary response message carries an IMRN;  And sending, by the S-CSCF, the temporary response message carrying the IMRN to the UE, where the UE initiates a CS call to the CSA through the IMRN, and completes the establishment of the CS access call leg. 14. The method according to claim 12, wherein the CSA is received The call request from the UE is: the CSA receives a call request sent by the UE by using a USSD message; and the establishing a CS access call leg with the UE is: the CSA sends an IMRN to the UE by using a USSD message. And the UE initiates a CS call to the CSA through the IMRN, and completes the establishment of the CS access call leg.  The method according to claim 14, wherein the call request further carries a non-real time media request.  The method according to claim 13 or 14, wherein the method for establishing another call leg with the opposite end is:  The CSA generates a call request to the peer end, and sends the call request to the peer end through the S-CSCF, and receives the peer return response message to complete establishment of another call leg with the opposite end.  The method according to claim 16, wherein before the sending the call request to the peer through the S-CSCF, the method further includes:  The S-CSCF sends the call request to the CCF according to an iFC check, and the CCF decides whether to support the VCC handover of the call: if supported, terminates the call request conversation, creates a new conversation, and passes the The new session sends a call request to the S-CSCF; otherwise, the call request is directly returned to the S-CSCF, and subsequent requests for this call will no longer pass through the CCF.  The method according to claim 16, wherein before the sending the call request to the peer end by using the S-CSCF, the method further includes:  The S-CSCF sends the call request to the TAS for service logic processing according to the iFC check, and the TAS returns a call request to the S-CSCF.  The method according to claim 12, wherein the establishing the CS access call leg between the UE and the UE comprises: Receiving, by the S-CSCF, the CSA carrying the real-time media through the CS network through the S-CSCF The network 7 carries the requested call request, terminates the conversation of the call request, and returns a temporary response message to the UE through the S-CSCF, where the temporary response message carries an IMRN to enable the UE to pass the The IMRN establishes a CS call to the CSA.  The method according to claim 12, wherein the establishing the CS access call leg between the UE and the UE comprises:  The CSA receives the call request sent by the UE through the USSD message, and sends the IMRN to the UE through the USSD message, so that the UE establishes a path of the CS call with the CSA through the IMRN.  The method according to claim 19 or 20, wherein the CSA establishes another call leg with the peer end, including:  The CSA generates a call request to the CCF and sends it to the S-CSCF; the S-CSCF sends the call request to the CCF according to the request of the call request to the Uniform Resource Locator URI;  Determining, by the request URI, the CCF to the call request as a VCC handover request, and sending a session modification message to the S-CSCF;  Sending, by the S-CSCF, the session modification message to the peer end, the peer end sends a response message to the S-CSCF for the session modification message; the S-CSCF sends the response message to the CSA, where The CSA completes the establishment of another call leg with the peer.  22. An IMS service providing system, the system comprising:  An S-CSCF, configured to receive a call request from a peer end and send the call request;  The ADSF is configured to receive a call request of the peer end sent by the S-CSCF, determine, according to the pre-stored decision parameter, the UE to receive the access network of the current call, and send the decision result by using a call request; The S-CSCF is further configured to receive a call request carrying a decision result from the ADSF, and send a call request according to the decision result; The CSA is configured to receive a call request sent by the S-CSCF according to the decision result, establish a CS access call leg with the UE, and receive an IMS service by using the CS access call leg.  The system according to claim 22, further comprising: an MGCF, configured to receive a CS call initiated by the UE during the process of establishing a CS access call leg by the CSA and the UE, and according to The CS call generates a SIP call request and sends to the CSA; the CSA generates a new call request and sends it to the S-CSCF.  24. The system of claim 22 or 23, wherein the system further comprises:  The TAS is configured to receive a peer call request sent by the S-CSCF, perform service logic processing according to the call request, and send a call request to the S-CSCF.  25. The system of claim 22 or 23, wherein the system further comprises:  a CCF, configured to receive a call request from the S-CSCF, and decide whether to support subsequent VCC handover of the call, if supported, terminate the conversation of the call request, and create a new conversation, and send a new conversation to the S-CSCF Send a call request; otherwise, return the call request directly to the S-CSCF.  26. An IMS service providing system, the system comprising:  The CSA is configured to receive a request for sending the UE and a call request for the IMS service by the opposite end, establish a CS access call leg with the UE, and establish another call leg with the peer end, by using the call leg Receive IMS services.  The system according to claim 26, wherein the CSA is further configured to send a call request, the system further comprising: an S-CSCF, configured to receive a call request from the CSA, and The call request is sent to the peer. The system according to claim 27, wherein the system further comprises: The MGCF is configured to: when the UE establishes a CS access call leg with the CSA, receive the CS call initiated by the UE, and generate a SIP call request according to the CS call, and send the call to the CSA; A new call request is generated and sent to the S-CSCF.  The system according to claim 27, further comprising: a CCF, configured to receive a call request sent by the S-CSCF, and determine whether to support VCC switching of the call subsequently, if Support, the session of the call request is terminated, and a new dialog is created, and the call request is sent to the S-CSCF through the new session; otherwise, the call request is directly returned to the S-CSCF.  The system according to claim 27, further comprising: a TAS, configured to receive a call request sent by the S-CSCF, perform service logic processing according to the call request, and The S-CSCF returns a call request.  The system according to claim 27, further comprising: a CCF, configured to receive a call request from the S-CSCF, and when determining that the call request is a VCC handover request, Sending a session modification message to the S-CSCF;  The S-CSCF is further configured to receive a session modification message from the CCF and send it to the peer end, and receive a response message sent by the peer end for the session modification message and send the response message to the CSA.  32. An IMS service providing method, the method comprising:  Receiving a call request sent by the peer end, and sending the call request to the ADSF decision UE to receive the access network of the current call;  Receiving a decision result from the ADSF;  Transmitting a call request to the CSA according to the decision result, so that the CSA establishes a CS access call leg with the UE, so that the UE receives the IMS service through the CS access call leg. 33. The method according to claim 32, wherein the determining UE receives The access network of the call includes: determining, according to the pre-stored decision parameters, the access network that the UE receives the call;  The decision parameters include: an access network used by the current UE in progress, a registration information of the CS and the IMS, an operator policy, a user preference, a UE capability, and one or any of the access network capabilities of the UE. combination.  34. The method according to claim 32, wherein the sending a call request to the CSA according to the decision result comprises:  The call request is processed according to the iFC check and sent to the CSA;  Alternatively, the call request is sent to the CSA through the P-CSCF.  35. The method according to claim 32, wherein the establishing an CS access call leg between the CSA and the UE comprises:  The CS A receives the call request sent by the S-CSCF, terminates the session of the call request, creates a new session, and sends a call request to the S-CSCF through the new session, where the call request carries the peer media request And the IMRN allocated by the CSA for this call;  The S-CSCF sends a call request received from the CSA to the UE;  The UE establishes a call leg by using the CS between the IMRN and the CSA. The method according to claim 32, wherein the establishing an CS access call leg between the CSA and the UE comprises:  The CS A receives the call request sent by the S-CSCF, terminates the session of the call request, and sends a call request to the UE through the CS network to complete the establishment of the CS access call leg.  The method according to claim 32, wherein, before receiving the call request sent by the opposite end, and sending the call request to the ADSF, the method further includes:  The call request is sent to the TAS for service logic processing according to the iFC check, and the call request returned by the TAS is received. 38. The method according to claim 32, wherein the receiving end sends The sent call request, before sending the call request to the ADSF, further includes: sending the call request to the CCF according to the iFC check;  Whether the CCF decision subsequently supports the VCC handover of the call: if supported, terminates the conversation of the call request, creates a new conversation, and returns a call request through the new conversation; otherwise, directly returns the call request, the current call Subsequent requests will no longer pass through the CCF.