WO2008154780A1

WO2008154780A1 - Method for implementing call hold service of ip multimedia subsystem centralized service

Info

Publication number: WO2008154780A1
Application number: PCT/CN2007/003573
Authority: WO
Inventors: Zhenwu Hao; Min Shen; Yuhong Qiang; Jun Wang
Original assignee: Zte Corporation
Priority date: 2007-06-19
Filing date: 2007-12-13
Publication date: 2008-12-24
Also published as: CN101330640A; CN101330640B

Abstract

A method for implementing call hold service of IP multimedia subsystem centralized service, wherein when a user equipment ICS_UE provided with IP multimedia subsystem, i.e. IMS centralized service capability, requests a call hold service, the IMS circuit switched control function ICCF sends a call hold request to the supplementary service server, and the supplementary service server provides control over the call hold service, while keeps the held user media plane active. With the invention, the service requirement for the call hold service of the IP multimedia subsystem centralized service could be achieved, the difficulty for realizing the service and the interaction complexity could be reduced, and the repeated occupancy of the media resource could be avoided.

Description

Method for realizing centralized service call maintenance service of IP multimedia subsystem

Technical field

The present invention relates to the field of communications, and in particular, to a method for implementing a call holding service in a centralized service of an IP multimedia subsystem.

Background technique

IP (Internet Protocol, IP for short) The Multimedia Subsystem (IMS) is an IP-based solution proposed by the 3rd Generation Partnership Project (3GPP). The network architecture, which builds an open and flexible business environment, supports multimedia applications, and provides users with rich multimedia services.

IMS is an IP-based telecommunications network architecture, independent of access technology, except for GPRS (General Packet Radio Service), WLAN (Wireless Local)

Area Network, WLAN, etc., can provide services for mobile cellular networks such as GSM (Global System for Mobile communications) and UMTS (Universal Mobile Telecommunications System). .

GSM, UMTS, and other mobile cellular networks use circuit-switching technology, called Circuit Switched (CS) domain, to provide users with basic voice services and supplementary services based on voice services. When the CS domain accesses the IMS, it evolves into an access mode, and the service is completely provided by the IMS. This technology is called IMS Centralized Service (ICS).

Figure 1 is an architecture diagram of the scenario in the IMS centralized control service, including the following network elements:

101 User Equipment (UE)

102 Visiting the Mobile Switch Center (VMSC)

103 Home Subscriber Server (HSS)

104 Media Gateway Control Function (MGCF) 105 Media Gateway (MGW)

106 IMS CS Domain Control Function (ICCF)

107 Call Session Control Function (CSCF)

108 Telephony Application Server (TAS), also known as supplementary service server.

The UE 101 establishes three paths to the IMS domain, namely: a session control path, a bearer control path, and a bearer path.

There are two ways for the session control path to transfer session information between the UE 101 and the ICCF 106.

(1) The CS session control path is carried on the CS domain, and the Unstructured Supplementary Service Data (USSD) is used. The path passes through the VMSC.

102 and HSS 103;

(2) The PS session control path is carried on the PS domain and adopts the Session Initial Protocol (SIP) protocol. The path passes through the IP bearer network and the CSCF 107 in the IMS domain.

The bearer control path controls the establishment of the bearer path and the management of the bearer resources. The UE 101 accesses the VMSC 102 by using standard CS control signaling, and accesses the IMS through the MGCF 104, and reaches the ICCF 106 via the CSCF 107.

The bearer path is that the UE 101 accesses the IMS through the VMSC 102 and the MGW 105 and establishes a media connection with the remote device of the session.

The IMS centralized service uses the session control path to exchange session control information between the UE 101 and the ICCF 106, and establishes and controls the media bearer through the bearer control path. The session control path and the bearer control path are merged at the ICCF 106. The ICCF 106 functions as an IMS user agent, and performs access to the IMS instead of the user equipment to form a remote call branch. The branch has an application server such as TAS 108 to provide IMS for the ICS-UE. business. The TAS 108 server can provide users with a number of supplementary services such as call hold, call transfer, and number display, and is therefore also called a supplementary service server.

The Call Hold service is a supplementary service in the communication system: When two users (User A and User B) establish a call in the communication system, one of the users (by User A) For example, the remote user (user B) can be temporarily requested to keep the current call connection without hang up, but no voice transmission is performed. While in the hold state, UE-A may request UE-B to re-enter the call state from the hold state, which is called Call Resume. Call hold services include two processes: call hold and call recovery.

On the basis of call hold, User A can then dial or answer a third party (User C) to establish a call with User C, and can switch between the hold call and the call state.

In the telecommunication service, the above-mentioned call holding process, call recovery process, and dialing or receiving third party telephone service based on call hold are generally referred to as call hold service. In this document, there is no special description, and the call hold service refers to the above-mentioned collective service.

As a telecommunications system, ICS must support call-holding services.

The implementation of call hold in ICS is shown in Figure 2.

UE-A is an ICS-capable UE. The VMSC, ICCF, MGCF, CSCF and other devices establish a call with the remote terminal UE-B, and establish a two-way media connection with the UE-B through the VMSC and the MGW. When User A wishes to initiate call hold, the following steps are included:

201. The UE-A sends a call hold request to the ICCF by using a session control path.

202. The ICCF sends a media update request message to the UE-B, requesting the UE-B to enter a hold state.

203. After the UE-B changes the media local media resource, return a media update success response to the ICCF.

204. At the same time as step 202, the ICCF sends a media update message to the MGCF, instructing the MGCF to control the MGW to enter an inactive state, and not receiving or transmitting the media stream;

205. After the MGCF controls the MGW to change the media resource, return a media update success response to the ICCF.

At this time, UE-A and UE-B enter the session hold state, and the media stream between the MGW and UE-B is interrupted.

The media stream is transmitted by a real-time transport protocol (RTP), and the real-time transport control protocol (RTCP) is used to control the transmission, and the monitoring, synchronization, and link keep-alive are performed. . When the media transmission is temporarily interrupted according to the service requirements, that is, the RTP data packet is not sent, it still needs to be transmitted on the link. RTCP packet, keeping the link active.

According to the above requirements, after the UE-A and UE-B enter the session hold state, the RTP packet is no longer transmitted, but the RTCP packet is still transmitted, and the link is not interrupted, which is indicated by a broken line in the figure.

In the call hold state, when the UE-A needs to call the third-party user UE-C, the following steps are included:

206, UE-A sends a call setup request to the ICCF through the session control path, calling the user C;

207, the ICCF sends an invite request to the UE-C, where the request carries the media information of the MGW, where the media information is the media information of the MGW used by the session in which the UE-A and the UE-B call;

208. The UE-C returns a ringing response.

209. The ICCF returns a ringing response to the UE-A through the session control path.

210, UE-C goes off-hook, UE-C returns a successful response;

211. The ICCF returns a connection response to the UE-A through the session control path.

212. The ICCF sends a success response confirmation message to the UE-C.

The above steps 206 to 212 are call setup processes, and include intermediate media negotiation, resource reservation, and the like, which are not illustrated in the figure for simplicity.

After the above steps are completed, the media between the UE-A and the UE-C may be ready to be connected, that is, the media plane connection of the MGW is moved from the UE-B to the UE-C, but the media of the user UE-B is maintained. The face will lose connection and the MGW will no longer be able to return RTCP packets to UE-B. UE-B may consider the media connection lost and release the held session.

In order to solve the above problem, the existing method utilizes a Media Resource Function Control (MRFC) / Media Resource Function Processor (MRFP) to provide media resources, and a UE that is kept alive. -B is connected to provide media-side keep-alive information of UE-B. The above-mentioned MRFC and MRFP are usually set together, collectively referred to as Media Resource Function (MRF), sometimes referred to as a media resource server, to provide IMS users with media conversion, media playback and other functions, wherein the MRFC is based on other business functions (such as The requirement to supplement the service call to maintain playback is to control the MRFP to provide corresponding media processing services (such as playback). Specific steps are as follows:

213. The ICCF sends an invite request to the MRF, where the media information of the UE-B is carried, and the MRFC in the MRF is requested to allocate the media resource corresponding to the UE-B media information.

214, the MRF allocates resources, and returns a successful response to the ICCF;

215, the ICCF sends a success response confirmation message to the MRF.

216. The ICCF sends a media update request to the UE-B, where the media resource information of the MRFP in the MRF obtained in the process of steps 213-215 is carried;

217. The UE-B updates the local media resource, establishes a media connection with the MRFP, and returns a successful response to the ICCF.

Through steps 213 to 217, the ICCF applies for the media resource to the MRFC/MRFP, and establishes a media connection between the UE-B and the MRFP to implement the requirement for maintaining the media plane of the UE-B.

218. The ICCF sends a media update request to the MGCF, where the request carries the media information of the UE-C, and indicates that the media resource is activated to enter a normal sending and receiving state.

219. The MGCF controls the MGW to update the media resource, and establish a media connection with the UE-C.

220. At step 218, the ICCF sends a media update request to the UE-C, indicating that the media resource is activated, and enters a normal sending and receiving state.

221. The UE-C updates the local media resource and establishes a media connection with the MGW.

Through the step 218 221, a media connection between the UE-C and the MGW is established, thereby implementing a call between the UE-A and the UE-C.

However, this implementation currently has the following problems:

The call hold service is a contract service. The IMS is provided by a special supplementary service server (TAS). When the user requests the call to maintain the service, the user can decide whether to allow the user to use the service according to the user's contract, and at the same time, the game is maintained. When the sound or the need of the media is maintained, the MRFC/MRFP is controlled to play a hold tone for the user.

In the existing implementation method, in order to realize the keep-alive of the user's media surface when calling a third-party user, a method of controlling the MRFC/MRFP to provide a keep-alive function by the ICCF is adopted. If the user has the need to play the hold tone at this time, there are two implementation methods, one is controlled by the ICCF. MRFC/MRFP playback, one is controlled by a dedicated supplementary service server for MRFC/MRFP playback. In the former manner, the ICCF is required to know the subscription information of the supplementary service of the user, and needs to interact with the supplementary service server, so that the supplementary service server does not perform the playback operation, and increases the complexity of the service implementation and interaction; the latter method, ICCF And the supplementary service server separately claimed that "i will media gateway control function / media gateway control processing resources, resulting in waste of resources.

In addition, according to the IMS centralized service, the ICCF replaces the UE to access the IMS, so that the user can use the service provided by the IMS, that is, the ICCF itself does not provide a specific service, and the specific service is provided by other entities in the IMS network, such as an application server, and These services can be shared by different access methods from the CS domain, or the PS domain. Therefore, the current implementation ICCF participates in the implementation of the service, increases the complexity of the ICCF, and is somewhat inconsistent with the original intention of the IMS centralized service.

In summary, the current ICS call hold method increases the difficulty of business implementation and the complexity of interaction, or causes excessive media resources.

Summary of the invention

The technical problem to be solved by the present invention is to provide a method for implementing call hold in a centralized control service of an IP multimedia subsystem, realizing the service requirement of the call hold service, reducing the difficulty of the service implementation and the complexity of the interaction, and avoiding the media resources. Repeat occupancy.

To solve the above problem, the present invention provides an IP multimedia subsystem centralized service call maintenance service implementation method, and when the user equipment ICS-UE having the IP multimedia subsystem, that is, the IMS centralized service capability, requests the call hold service, the IMS circuit domain control function The ICCF sends a call hold request to the supplementary service server, and the supplementary service server provides control of the call hold service, while realizing the media coverage of the held user.

Further, the implementation method provided by the present invention may also have the following features:

The method is further divided into the following steps:

(a) User equipment ICS with IMS centralized service capability. The UE establishes a call with the remote user. The ICS-UE sends a call hold request to the IMS circuit domain control function ICCF. After receiving the ICCF, the ICCF sends a media update to the remote user. Request that the request passes through the supplementary service server in the remote call branch session path; (b) after the supplementary service server receives the media update request, to the media resource function

The MF applies for the media resource, and after receiving the media resource, sends a media update request to the remote user, and controls the remote user to establish a media connection with the media resource function processor MRFP in the MRF, and the MKFP sends the media surface keep-alive information to the remote user. .

The step (b) further includes the step (c): after the call is successfully maintained, for example, the ICS-UE calls the third-party user through the session control path, and the ICCF initiates a session establishment request to the third-party user through the supplementary service server, The request carries the media resource information of the media gateway MGW, requesting to establish a connection between the third-party user and the MGW, and the ICCF sends a media update request to the media gateway control function MGCF, instructing the MGCF to control the MGW to enter an activation state, thereby establishing an ICS-UE. Media connection with third-party users.

Step (b) is further divided into the following steps:

Step 303: After receiving the media update request, the supplementary service server finds that the user subscribes to the call to hold the service, and sends an invitation request to the MRF, requesting to send the media surface keep-alive information or play the media resource of the hold tone to the remote user;

Step 304: The MRF allocates resources, and returns a successful response to the supplementary service server. Step 305: The supplementary service server sends a media update request to the remote user, where the media resource information of the MRFP in the MRF obtained in the process of steps 303-304 is carried;

Step 306: After the remote user changes the media local media resource, establish a media connection with the MRFP, and return a media update success response to the supplementary service server.

Step 307: The supplementary service server returns a success response corresponding to the media update request to the ICCF.

In the step (a), the ICCF sends a media update or re-invitation request to the MGCF while initiating a call hold request to the remote user, instructing the MGCF to control the media resources of the MGW to enter an inactive or only transmit state.

Further, the implementation method provided by the present invention may also have the following features: In the step (b), when the supplementary service server applies for the media resource to the media resource function, or when the remote user establishes a media connection with the MRFP and the MGW is in an inactive or only transmitting state, If the MGW needs the keepalive of the media plane, the supplementary service server or ICCF applies for the media resource to the MRF, and sends a media update request to the MGCF, and the MGCF controls the MRFP in the MGW and the MRF to establish a media connection between the MGW and the MRPP. Transfer media stream or media surface keepalive information.

When the supplementary service server controls to establish a connection between the MGW and the MRFP, the following steps are included:

Step 310: The supplementary service server or the ICCF sends an invitation request to the MRF, carries the media information of the MGW, and clarifies the media resource. Step 311: The MRF allocates the resource, and returns a successful response to the supplementary service server or the ICCF, where the supplementary service server receives After the response, the device sends a media update request to the ICCF, where the request carries the media information of the acquired MRFP;

Step 312, the ICCF sends a media update request to the MGCF.

Step 313, the MGCF controls the MGW to change the media resource, and returns a media update success response. Step 314: The ICCF returns a media update success response to the supplementary service server.

Step (c) The resource corresponding to the MGW media resource information carried in the session establishment request initiated by the ICCF to the third-party user is the resource used by the ICS-UE to call the previous user.

In the step (a), the supplementary service server or the ICCF requests a media resource from the MRF, and sends a media update request to the MGCF, where the MGCF controls the MGW and the MRFP to establish a media connection, and transfers the media stream or media between the MGW and the MRFP. Face keeping information;

In the step (c):

When the media plane connection between the MGW and the third party user is established, or when the ICSJJE has no third party call in progress, and the ICS-UE and UE-B are interrupted by the held session, The supplementary service server or the ICCF releases the connection resource with the MGW on the MRJFP; when the ICS-UE has no third-party call in progress, and the ICS-UE and the UE-B session are restored, the supplementary service server or ICCF is released or waiting ICS—The UE and UE-B session release the connection resources with the MGW on the MRFP.

The releasing the connection resource with the MGW on the MRFP includes the following steps:

Step 329: The supplementary service server or ICCF sends a release request to the MRF. Step 330: The MRFC in the MRF instructs the MRFP to release the related resource, and returns a successful response to the supplementary service server or ICCF.

According to the implementation method of the present invention, the call maintenance service is controlled by the supplementary service server, and the keep-alive tone or the media surface keep-alive information is provided to the held user, and the ICCF only controls the MGCF/MGW according to the user request, so that the ICCF does not need to be used. By controlling the MRFC/MRFP, the supplementary service server can simultaneously serve different access modes while simplifying the functions of the ICCF. BRIEF abstract

Figure 1 is an architectural diagram of the IMS centralized control service;

Figure 2 is a flow chart of the existing ICS call hold service;

3 is a flow chart of an ICS call hold service according to an embodiment of the present invention. Preferred embodiment of the invention

In practical applications, the call-holding service is controlled and provided by the supplementary service server. At the same time, it is generally required that the network maintains a hold tone for the held user, and when the hold tone is played, the media connection and link are realized. Keep alive.

Based on the above considerations, the method for implementing call hold of the IP multimedia subsystem centralized service provided by the present invention provides the call maintenance service control by the supplementary service server, and at the same time, keeps the user's voice-activated or media-side keep-alive connection to ensure the Keep the user from being abnormally released because the media side is not connected. The implementation of the call hold service of the present invention generally includes the following steps:

(a) User equipment ICS with IP multimedia subsystem, ie IMS centralized service capability, the UE establishes a call with the remote user, and the ICS-UE sends a call hold request to the IMS circuit domain control function ICCF, and the ICCF receives the far-end request. The end user sends a media update request, and the request passes through the supplementary service server in the session path of the remote call branch;

(b) after receiving the media update request, the supplementary service server applies for a media resource to the media resource function (the media resource function controller MRFC/media resource function processor MRFP), obtains the media resource, and sends the media to the remote user. Updating the request, controlling the remote user to establish a media connection with the MRFP, and the MRFP keeps the user playing the hold tone or sending the media surface keep-alive information to the remote end;

(c) After the call is successfully maintained, if the ICS-UE calls the third-party user through the session control path, the ICCF initiates a session establishment request to the third-party user, requesting to establish a connection between the third-party user and the media gateway MGW, and at the same time ICCF Sending a media update request to the media gateway control function MGCF, instructing the MGCF to control the MGW to enter an active state, thereby implementing a media connection between the ICS-UE and the third-party user.

The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

3 is an implementation process of an embodiment of the present invention, where UE-A is an ICS-capable UE, and a call with a remote terminal UE-B is established through a VMSC; ICCF, MGCF, CSCF, TAS, and the like. The TAS is always on the session path of the far-end call branch, and establishes a two-way media connection with the UE-B through the VMSC MGW.

If user A subscribes to the call hold service and needs to initiate call hold service, the call hold service implementation includes the following steps:

301. The UE-A sends a call hold request to the ICCF by using a session control path.

302. The ICCF sends a media update request message to the UE-B through the TAS, requesting the UE-B to enter a hold state.

303. After receiving the media update request of the call hold service, the TAS sends a request for the subscription to the MRF, and sends an invitation request to the MRF, where the TAS carries the media information of the UE-B, and sends a media plane keep-alive message or broadcasts for the UE-B. Keep the media resources of the sound;

304, the MRF allocates resources, and returns a successful response to the TAS; 305. The TAS sends a media update request to the UE-B, where the media resource information of the MFP in the MRF obtained in step 303304 is carried.

306. After the UE-B changes the media local media resource, establish a media connection with the MRFP, and return a media update success response to the TAS.

307. The TAS returns a successful response corresponding to the media update request (step 302) to the ICCF.

308. At the same time as step 302, the ICCF sends a media update message or a re-invitation request to the MGCF, instructing the MGCF to control the MGW to enter an inactive state, and not receiving or transmitting the media stream;

309. After the MGCF controls the MGW to change the media resource, return a media update success response to the ICCF.

In step 308, the ICCF may also send a media update message or a re-invitation request to the MGCF, instructing the MGCF to control the MGW to enter a transmit-only state, that is, only transmit and not receive.

After the above steps are completed, the UE-B enters the session hold state, and the MRFP plays the hold tone or the media plane keep-alive information (the RTCP packet) to the UE-B. If no tone is required at this time, that is, there is no RTP packet, MRPP and UE-B still need to send RTCP packets to keep the media connection alive.

At this time, the media resources of the MGW on the IMS side are inactive, do not send or receive media streams, and are not connected to the media planes of other devices. If the MGW also needs the media plane to keep alive, then the TAS or ICCF needs to apply for the media resource to the MRFC/MRFP, establish a media connection with the MGW, and transmit the RTCP data packet to maintain the MGW media connection. See the steps in the dotted box for the specific process:

310. The TAS sends an invite request to the MRFC/MRFP, and carries the media information of the MGW to apply for the media resource. Steps 310-315 may be performed after step 306, or may be performed at the same time as step 303. No steps 308-309 are required

311, the MRFC/MRFP allocates resources, and returns a successful response to the TAS;

312. The TAS sends a media update request to the ICCF, where the request carries the media resource information of the MRFP obtained in steps 311 312 to 312;

313. The ICCF sends a media update request of step 312 to the MGCF. 314, after the MGCF controls the MGW to change the media resource, returning a media update success response;

315, the ICCF returns a media update success response to the TAS;

After steps 310-315, the MGW establishes a media connection with the MRFP, and transmits media stream or media surface keep-alive information between the MGW and the MRFP, thereby realizing the requirement for the MGW resource to be saved.

This example only describes the case where the TAS applies for the media resource. If the ICCF performs the above process, the ICCF directly requests the resource from the MRF, and then sends a media update request to the MGCF to establish a media connection between the MGW and the MRFP.

In the call hold state, when the UE-A needs to call the third-party UE UE-C, the following steps are included:

316, UE-A sends a call setup request to the ICCF through the session control path, and calls the third-party user C;

317, the ICCF sends an invite request to the UE-C, where the request passes the TAS, and the request carries the media resource information of the MGW, where the media resource information is the media resource information of the MGW used by the session between the UE-A and the UE-B;

318. The TAS forwards an invitation request to the UE-C to request to establish a session.

319, UE-C starts ringing, and returns a ringing response to the TAS;

320, the TAS forwards the ringing response to the ICCF;

321. The ICCF returns a ringing response to the UE-A through the session control path.

322. When user C picks up the phone, UE-C returns a successful response to the TAS.

323, the TAS forwards a successful response to the ICCF;

324. The ICCF returns a successful response to the UE-A through the session control path.

325. The ICCF sends a success response confirmation message to the TAS.

326. The TAS forwards a success response confirmation message to the UE-C.

327. The ICCF sends a media update request to the MGCF, where the request carries the media information of the UE-C, and instructs the MGCF to control the MGW to enter an active state.

328. The MGCF controls the MGW to enter an active state, and after establishing a media connection with the UE-C, ICCF returns a successful response;

Between steps 318 and 319, there may be media negotiation with the UE-C, and the resource reservation process is not illustrated in the figure for simplicity. Through the negotiation process, the media format used between the UE-C and the MGW is determined. The media information of the UE-C carried in step 327 is obtained through the process.

Steps 327-328 are generally performed before step 319. In addition, after the media negotiation and resource reservation are successful, the same activation operations of steps 327-328 may be performed, so that if the third-party user has a personalized ringtone service, ICS—The UE can hear the ringback tone of the other party.

After the above steps 316-328 are completed, the media between UE-A and UE-C is connected (via VMSC, MGW), that is, the media plane of the MGW is connected to UE-C, and UE-A and UE-C are implemented. Between calls.

If the MGW performs media plane preservation, that is, steps 310-315 are performed, the situation that the resource connected to the MGW needs to be released on the MRFP includes: After completing step 316 328, the media plane connection of the MGW is moved from the MRFP to the UE-C; Or, when the ICS-UE has no third-party calls in progress, and at this time, the ICS-UE and the UE-B session are restored (the MGW's media resources are reconnected to the UE-B); or, when the ICS-UE is not in progress When a three-way call occurs, the ICSJJE and UE-B are suspended for some reason. All of the above three cases will result in the loss of the connection between the MRFP and the MGW. Therefore, it is necessary to release the connection resources with the MGW on the MRFP.

The specific steps for the TAS to request the release of the MRFP and MGW connection resources are as follows:

329. The TAS sends a release request to the MRF.

330. The MRFC in the MRF instructs the MRFP to release related resources and return a successful response to the TAS;

When the ICS-UE has no third-party calls in progress, and the ICS-UE and UE-B sessions are restored at this time, since the user may use the hold function again, the MRFP resources may not be released temporarily during recovery. The state is not activated, but the MRFP resource is released after the ICS-UE and UE-B session ends.

If the resource is requested by the ICCF, if any of the three conditions described above for releasing the resource connected to the MGW on the MRFP occurs, the ICCF requests to release the MRFP resource, and the release process is similar to the TAS release process. As described above, since the user may use the hold function again, when the media connection of the MGW is moved from the MRFP to the remote device, the MRHP resource is temporarily released, so that it is in an inactive state, but waits until the end of the entire session. Release MRFP resources.

It can be seen from the above process that the method of the present invention implements the business process of the ICS call maintenance service, and the call maintenance service function through the supplementary service server is used.

The ICCF operates the requirements of the MRFC/MRFP, while the supplementary service server provides the unified service requirements for users of different access modes.

Of course, the invention may be embodied in various other forms without departing from the spirit and scope of the invention.

Industrial Applicability The method of the present invention controls the call hold service through the supplementary service server, so that the ICCF no longer needs to control the MRFC/MRFP, simplifies the function of the ICCF, and reduces the difficulty of the service implementation and the complexity of the interaction on the basis of implementing the ICS call hold service. Degree, while avoiding the repeated occupation of media resources. In addition, the supplementary service server can also provide services for different access modes at the same time, improving system compatibility.

Claims

Claim

A method for implementing a centralized service call hold service of an IP multimedia subsystem, characterized in that, when a user equipment ICS-UE having an IP multimedia subsystem, that is, an IMS centralized service capability, requests a call hold service, the IMS circuit domain control function ICCF The call hold request is sent to the supplementary service server, and the supplementary service server provides control of the call hold service, and at the same time, the media surface of the held user is kept alive.

2. The method according to claim 1, wherein the method is further divided into the following steps:

(a) User equipment ICS with IMS centralized service capability. The UE establishes a call with the remote user. The ICS-UE sends a call hold request to the IMS circuit domain control function ICCF. After receiving the ICCF, the ICCF sends a media update to the remote user. Request that the request passes through the supplementary service server in the remote call branch session path;

(b) after receiving the media update request, the supplementary service server applies for the media resource to the media resource function MRF, obtains the media resource, and sends a media update request to the remote user to control the media resource function of the remote user and the MRF. The processor M FP establishes a media connection, and the MRFP keeps the user's media surface keep-alive information to the remote end.

3. The method according to claim 2, wherein:

The step (b) further includes the step (c): after the call is successfully maintained, if the ICS-UE calls the third-party user through the session control path, the ICCF initiates a session establishment request to the third-party user through the supplementary service server, requesting The media resource information carrying the media gateway MGW is requested to establish a connection between the three-party user and the MGW, and the ICCF sends a media update request to the media gateway control function MGCF, instructing the MGCF to control the MGW to enter an activation state, thereby establishing an ICS-UE and Media connection between third-party users.

4. The method according to claim 2, wherein:

The step (b) further includes the following steps:

Step 303: After receiving the media update request, the supplementary service server finds that the user subscribes to the call to hold the service, and sends an invitation request to the MRF, requesting to send the media face to the remote user. Information or play media resources that maintain sound;

5. The method according to claim 2 or 4, characterized in that:

In the step (a), the ICCF sends a media update or re-invitation request to the MGCF, while instructing the MGCF to control the media resources of the MGW to enter an inactive or only sending state, while sending a call hold request to the remote user. .

6. The method according to claim 2, wherein:

In the step (b), when the supplementary service server applies for the media resource to the media resource function, or when the remote user establishes a media connection with the MRFP and the MGW is in an inactive or only transmitting state, If the MGW needs the keepalive of the media plane, the supplementary service server or the ICCF requests the media resource from the MRF, and sends a media update request to the MGCF, and the MGCF controls the MRFP in the MGW and the MRF to establish a media connection between the MGW and the MRFP. Transfer a body stream or media surface keepalive information.

The method according to claim 6, wherein the method for saving the MGW media surface further comprises the following steps:

Step 310: The supplementary service server or the ICCF sends an invitation request to the MRF, and carries the media information of the MGW to apply for a certain physical resource. Step 311: The MRF allocates the resource, and returns a successful response to the supplementary service server or the ICCF, where the supplementary service server receives After the response, the device sends a media update request to the ICCF, where the request carries the media information of the acquired MRFP;

Step 312, the ICCF sends a media update request to the MGCF. Step 313, the MGCF controls the MGW to change the media resource, and returns a media update success response. In step 314, the ICCF returns a media update success response to the supplementary service server.

8. The method according to claim 3, wherein:

9. The method according to claim 3, wherein:

In the step (a), the supplementary service server or ICCF requests a media resource from the MRF, and sends a media update request to the MGCF, and the MGCF controls the MGW to establish a media connection with the MRFP, and transmits the media stream or media between the MGW and the MRFP. Face keeping information;

In the step (c):

When the media plane connection between the MGW and the third party user is established, or when the ICS-UE has no third party call in progress, and the held session of the ICSJJE and the UE-B is interrupted, the supplementary service server or The ICCF releases the connection resources with the MGW on the MRFP;

When the ICS-UE has no third-party calls in progress, and the ICS-UE and UE-B sessions are restored, the supplementary service server or ICCF releases or releases the MRFP after the ICS-UE and UE-B sessions are over. Connect resources to the MGW.

10. The method according to claim 9, wherein:

The connection resource with the MGW on the dry-release MRFP includes the following steps:

Step 329: The supplementary service server or the ICCF sends a release request to the MRF. In step 330, the MRFC in the MRP instructs the MRFP to release related resources, and returns a successful response to the supplementary service server or ICCF.