WO2008151487A1

WO2008151487A1 - Implementation method of finishing calling in ims centralized control service

Info

Publication number: WO2008151487A1
Application number: PCT/CN2007/003477
Authority: WO
Inventors: Zhenwu Hao; Zhendong Li; Shilin You
Original assignee: Zte Corporation
Priority date: 2007-06-14
Filing date: 2007-12-06
Publication date: 2008-12-18
Also published as: CN101325734A; CN101325734B

Abstract

An implementation method of finishing the calling in IMS centralized control industry,includes the following steps:(a)after receiving the session request message by the calling user of the remote end, IMS ICCF sending the session request to the called user equipment UE by the packet switch PS domain, wherein the message is carrying the message about the address of ICCF and the session identification; (b)after the called user equipment UE receiving the session request message, initializing the calling establishing request for the ICCF by the circuit switched CS domain and carrying the session identification message, and after the ICCF receiving the calling establishing request, associating the session initialized by the called user equipment UE and the calling user of the remote end according to the session identification message.

Description

Method for implementing terminal call in IMS centralized control service

Technical field

The present invention relates to the field of communications, and more particularly to a method for implementing a terminating call in an IMS centralized control service. Background technique

IP (Internet Protocol, IP for short) 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, and has nothing to do with access technology. In addition to providing services for packet access networks such as GPRS (General Packet Radio Service) and WLAN (Wireless Local Area Network). It can also provide services for mobile cellular networks such as GSM (Global System for Mobile communications) and UMTS (Universal Mobile Telecommunications System).

Mobile cellular networks such as GSM and UMTS use circuit switching technology, called Circuit Switched (CS) domain, to provide 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).

The IMS centralized service has the following advantages:

(1) IMS provides consistent services for access modes such as circuit domain and packet domain, and supports network convergence;

(2) Supporting the evolution of the CS network to the IMS network;

(3) Support not only ICS-capable user equipment, but also existing ICS-capable capabilities User equipment.

The present invention is applicable to a user equipment (UE) that simultaneously accesses a circuit switched CS domain and a packet switched (PS) domain. However, its PS is low-speed IP access and cannot provide voice services. Figure 1 is an architectural diagram of the scenario in the IMS centralized control service, such as the following network element:

101 User Equipment (UE)

102 Visiting the Mobile Switching Center (VMSC)

103 Media Gateway Control Function (MGCF)

104 Call Session Control Function (CSCF) 105 Media Gateway (MGW)

106 IMS CS Control Function (ICCF). In the IMS domain, the function of ICCF is also Application Server (AS).

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

The session control path is established on the PS domain, and the UE 101 is directly connected to the IMS core network through the PS domain. The bearer control path, the UE accesses the VMSC by using standard CS control signaling, and accesses the IMS through the MGCF, and the VMSC is integrated. The ISDN User Part (ISUP) is sent to the MGCF_103, and then the Session Initial Protocol (SIP) is used to reach the ICCF-106 through the CSCF-104. The bearer path is established through the MGW-105. .

The session control path transfers session information between the UE-101, the CSCF-104, and the ICCF-106, and the bearer control path passes the ^seven- load control message between the CS domain and the IMS domain through standard CS control signaling and SIP signaling. Finally, the two control paths are associated with ICCF-106. This function is equivalent to the SIP user agent function that the UE establishes an IMS session. The bearer control path also controls the establishment of the bearer path and the management of the bearer resources.

Figure 2 is the process of terminating (called) of the existing scheme. The specific process is as follows:

201) The CSCF of the serving terminating UE (ie, the called UE.) receives the SIP session request; 202) The ICCF receives the SIP session request sent by the CSCF;

203) ICCF acquires the roaming number of the called party;

204) The ICCF acts as a back-to-back proxy for the terminating UE (Back to Back User Agent,

B2BUA), sending a SIP session request to the terminating UE, the message is first forwarded to the CSCF;

205) the CSCF forwards the SIP session request to the terminating UE;

206) The terminating UE returns a SIP session to the CSCF to send a message;

207) The CSCF forwards the SIP session ongoing message to the ICCF;

208) The ICCF initiates a SIP invite message to the terminating UE by using the CS domain roaming number of the terminating UE, and the message is first sent to the CSCF;

209) The CSCF forwards the SIP invite message to the MGCF;

210) The MGCF sends an initial address message of the ISUP to the VMSC of the serving terminal UE;

211) The VMSC initiates a call setup message to the UE;

212) The terminating call UE returns a successful SIP response to the CSCF;

213) The CSCF returns a SIP successful response to the ICCF;

214) The user picks up the phone, and the terminal sends a connection message to the VMSC.

215) The VMSC sends an ISUP response message to the MGCF;

216) The MGCF returns a SIP successful response to the CSCF;

217) The CSCF returns a SIP successful response to the ICCF;

218) The ICCF returns a SIP successful response to the CSCF;

219) The CSCF returns to the calling party and the SIP responds successfully, and enters the call state.

It can be seen from the termination process of the existing call that the current call process may require two paging processes, and the call setup time is relatively long. In addition, the terminal call must require the ICCF to obtain a roaming number of the terminating UE when the ICCF establishes a terminating call bearer control path with the VMSC. The ICCF uses the roaming number and the VMSC to establish a bearer control path, but how the ICCF obtains the number is not yet defined. Summary of the invention

The problem to be solved by the present invention is to provide a method for implementing a terminating call in an IMS centralized control service, which shortens the duration of the terminating call establishment.

The invention utilizes the circuit domain calling process to establish a circuit domain bearer manner, and implements the ICS terminal call. In order to solve the above technical problem, the present invention provides a method for implementing a terminal call in an IMS centralized control service, including the following steps:

(a) After receiving the session request message of the remote calling user, the IMS circuit domain control function ICCF sends a session request to the called user equipment UE through the packet switched PS domain, where the message carries the address information and the session identifier of the ICCF. Information

(b) after receiving the session request message, the terminating UE initiates a call setup to the ICCF through the circuit switched CS domain and carries the session identification information, after receiving the call setup request, the ICCF receives the call setup request, according to the The session identification information associates a session initiated by the terminating UE with a session initiated by the remote calling party. After the initiated session association, the call session control function CSCF sends a SIP ringing message to the calling side.

Further, step rubber (b) is also included

(c) after the terminating user picks up the phone, the terminating UE sends a success response message to the ICCF through the session control path of the PS domain;

(d) After receiving the success response message, the ICCF sends a successful response to the calling side via the call session control function CSCF to complete the connection of the session.

Further, the address information and session identification information of the ICCF are dynamic ICCF routing numbers, or static ICCF routing numbers and reference information capable of uniquely identifying a session.

Further, after receiving the call setup request of the terminating UE, the ICCF in step (b) sends a ringing message to the terminating UE through the bearer control path of the CS domain, to notify the terminal call UE that the call setup is successful. Further, the calling UE starts ringing after receiving the ringing message sent by the ICCF, and returns a session initial protocol SIP ringing message to the ICCF through the PS domain. Further, after receiving the success response message, the ICCF in step (d) also sends a SIP acknowledgment message to the terminating UE through the session control path of the PS domain.

Further, after receiving the success response message, the ICCF of the step (d) returns a success response message to the terminating UE, and the message is forwarded by the CSCF to the media gateway control function MGCF, and the MGCF sends a service to the terminating UE. The visited mobile switching center VMSC returns an ISUP response message, and the VMSC sends a connection message to the terminating UE.

Further, in step (a), the session request message sent by the ICCF to the terminating UE further carries a calling number; and step (b) the terminating UE displays the calling number after receiving the session request message. .

Further, after step (d), the calling side user or the media gateway establishes a bearer connection with the media gateway on the called side, and connects the resources of the calling user and the called user.

Further, the message between the called UE and the ICCF is transmitted in the CS domain through the bearer control path, that is, through the visited mobile switching center VMSC, the media gateway control function MGCF, and the call session control function CSCF; the called UE and the ICCF The message between the PS domain is transmitted through the CSCF through the session control path.

By adopting the method of the present invention, the ICS termination call process is established by the UE re-calling the ICCF address, the paging time is saved, and the ICCF is not required to acquire the roaming number, which provides a solution for the ICS termination call. BRIEF abstract

Figure 1 is a system architecture diagram for implementing IMS centralized control services;

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

FIG. 3 is a schematic diagram of an ICS terminal call service flow according to the embodiment; FIG.

FIG. 4 is a flow chart of the ICS terminal call service according to the embodiment. Preferred embodiment of the invention The present invention will be further described in detail below in conjunction with the drawings and specific embodiments.

As shown in FIG. 3, in the process of terminating, the ICCF of the home network of the terminating UE acts as a B2BUA, and after receiving the session request sent by the calling party, the session request is sent to the terminating UE through the PS domain (step 301). After receiving the message, the UE initiates a call to the ICCF in the CS domain (step 302). After receiving the session request forwarded by the CS domain, the ICCF forwards the ringing message to the originating side.

303), after the terminating user picks up the phone, the terminating UE sends a successful response to the ICCF through the PS domain (step

304) After receiving the successful response sent by the PS domain, the ICCF sends a successful response to the UE, and completes the connection of the session (step 305).

It can be seen that there are 3 sessions in the originating end to the terminating call UE, one is the session A from the originating end to the ICCF, one is the session B in which the ICCF terminates the call to the UE through the PS domain; Session C where the ICCF initiates the call. The purpose of session B is to inform the UE that there is an incoming call and call related information, and to assist in the establishment of session C, which does not generate an actual bearer. Session C completes the establishment of the bearer in the CS domain. In the above step 305, session A and session C are connected.

By carrying the dynamic routing number of the ICCF through session B, the UE initiates the calling by using the dynamic routing number of the ICCF, and the ICCF uses the number to associate the two. In addition, other methods are not excluded. For example, if the UE configures a static ICCF routing number, the ICCF calls the UE through the session B, and carries some reference information (such as a random number generated by the network side). When the UE initiates the session C, the static The ICCF routing number carries the reference information at the same time, and the ICCF uses the reference information to associate.

FIG. 4 is an implementation process of the embodiment, including the following steps:

401) The CSCF receives the SIP session request (session A) of the remote calling side;

402) The ICCF receives the SIP session request (session A) forwarded by the CSCF;

403) The ICCF determines, by using the obtained called information, the UE that is called to support the ICS, and allocates a dynamic ICCF routing address. At this time, the ICCF acts as a B2BUA, and initiates a SIP call (session B) to the terminating user through the PS domain, and establishes a UE call to the UE. The session control path, the SIP session request message carries the assigned dynamic ICCF routing address, and the message is first sent to the CSCF;

In addition to allocating dynamic ICCF routing addresses (ie, ICCF routing numbers) for this call, ICCF can also use other address information and session identification information, such as static ICCF routing addresses and capable IP addresses. A reference information identifying the session, and carrying the information in the SIP call request message, enabling the UE to call the ICCF in the CS domain, and also making the call established by the terminating UE, that is, the call received by the session C and the CSCF, Session A can be associated.

In another embodiment, the session request message may further carry the calling number information, and the terminating UE may display the calling number to the user according to the received calling number information.

404) The CSCF forwards the received SIP session request to the terminating UE (session B) through the PS domain;

405) After receiving the SIP session request message, the UE uses the ICCF address as the called number to initiate call setup (session C) to the VMSC;

406) The VMSC sends an initial address message (session C) to the MGCF according to the ICCF address. If the UE has the calling intelligent service, the smart trigger data may be configured, so that the VMSC does not trigger the call of the UE that is called the ICCF address. Call smart business.

407) the MGCF sends the session request to the CSCF according to the ICCF address in the session request message (session C);

408) The CSCF sends a SIP call request to the ICCF according to the ICCF address (session C); in steps 405-408, the calling process of the UE is simulated to establish a link, and the link can be established without the ICCF paging down from the CS domain. It saves time for call setup.

409) The ICCF associates the session A received in step 402 with the session C received in step 408 according to the received identification information, such as the dynamic ICCF routing address, and sends a ringing message (session C) to the CSCF;

410) The CSCF returns a ringing message (session C) to the MGCF;

411) The MGCF returns an address full message to the VMSC (session C);

412) The VMSC returns a ringing message (session C) to the UE;

In step 409-412, the ICCF sends a ringing message to the terminating UE through the bearer control path of the CS domain to notify the UE that the call setup is successful, but the notification from the ICCF to the UE is not limited to the SIP ringing message, and other messages may be used.

413) The UE starts ringing, and sends a ringing message (session B) to the ICCF through the PS domain, and the message is first sent to the CSCF; 414) The CSCF wins the ringing message and forwards it to the ICCF (session B);

Steps 413 and 414 are responses to steps 403 and 404, which do not affect the connection of the ICCF, and may be omitted. After the step 408, the ICCF directly performs the subsequent step 415, that is, sends a ringing message to the calling side, which speeds up the connection. speed.

415) The ICCF notifies the calling side ringing (session A), and the ICCF sends a ringing message to the CSCF;

416) The CSCF sends a ringing message to the calling side (session A);

417) The terminal call UE picks up the phone, and the UE sends a success response message SIP 200 OK (session B) to the ICCF through the PS domain, and the message is first sent to the CSCF;

418) The CSCF forwards the success response message SIP 200 OK (session B) to the ICCF;

419, 420) The ICCF sends a SIP confirmation message (session B) to the terminating UE through the CSCF in the PS domain;

421) The ICCF returns a success response message SIP 200 OK (session C) to the terminating UE, and the message is first sent to the CSCF;

422) The CSCF forwards the success response message to the MGCF SIP 200 OK (session C );

423) The MGCF returns an ISUP response message (session C) to the VMSC serving the terminating UE;

424) The VMSC sends a connection message to the terminating UE (session C);

425, 426) The ICCF sends a success response message to the calling side SIP 200 OK (session A); after step 426, both parties enter a normal call.

Steps 419, 421, and 425 can be performed in parallel.

427) The calling party sends a SIP confirmation message to the CSCF (session A);

428) The CSCF sends a SIP acknowledgment message to the ICCF (session A);

429) The MGCF sends a SIP acknowledgement message to the CSCF (session C);

430) The CSCF sends a SIP acknowledgment message (session C) to the ICCF.

At this point, the calling side user or the media gateway establishes a bearer connection with the media gateway on the called side, thereby connecting the resources of the calling user and the called user.

Some of the above steps, such as steps 413-414, 419-420, 427-430, are only used as messages. Integrity is needed.

In other embodiments, the called user may also choose to hang up the session or initiate other processes, such as call forwarding, as needed during step 417.

It can be seen from the above process that the method of the present invention implements the ICS UE terminating service flow. Because the terminating UE actively initiates the call setup, the calling process is simulated to establish a link, and the ICCF does not need to look down in the CS domain. The call time is greatly shortened, the call failure caused by the long call time is avoided, and the channel resources are saved. In addition, the calling process is also used to unify the process in the IMS.

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

Industrial applicability

By adopting the method of the present invention, the ICS terminating process is established by the UE re-calling the ICCF address, the paging time is saved, and the ICCF is not required to allocate the roaming number, which provides a solution for the ICS terminal call.

Claims

Claim

1. A method for implementing a terminal call in an IMS centralized control service, comprising the following steps:

(b) after receiving the session request message, the terminating UE initiates a call setup to the ICCF through the circuit switched CS domain and carries the session identification information, after the ICCF receives the call setup request, according to the The session identification information associates a session initiated by the terminating UE with a session initiated by the remote calling party.

2. The method of claim 1 wherein:

Step (b) After the ICCF associates the session initiated by the terminating UE with the session initiated by the remote calling party, the call session control function CSCF sends a SIP ringing message to the calling side.

3. The method according to claim 1 or 2, characterized in that after step (b) further comprises

4. The method of claim 1 wherein:

The address information and session identification information of the ICCF are dynamic ICCF routing numbers, or are static ICCF routing numbers and reference information capable of uniquely identifying a session.

5. The method of claim 1 wherein:

After receiving the call setup request of the terminating UE, the ICCF sends a ringing message to the terminating UE through the bearer control path of the CS domain to notify the terminal UE that the call setup is successful.

6. The method of claim 5, wherein

After receiving the ringing message sent by the ICCF, the terminating UE starts ringing and passes through the PS domain to the office. The ICCF returns the session initial protocol SIP ringing message.

7. The method of claim 3, wherein

After receiving the success response message, the ICCF sends a SIP acknowledgment message to the terminating UE through the session control path of the PS domain.

8. The method of claim 3, wherein

After receiving the success response message, the ICCF returns a success response message to the terminating UE, and the message is forwarded by the CSCF to the media gateway control function MGCF, and the MGCF moves to the serving terminal UE. The switching center VMSC returns an ISUP response message, and the VMSC sends a connection message to the terminating UE.

9. The method of claim 1 wherein:

Step (a) The session request message sent by the ICCF to the terminating UE further carries a calling number; and step (b) the terminating UE displays the calling number after receiving the session request message.

10. The method of claim 3, wherein

After the step (d), the calling side user or the media gateway establishes a bearer connection with the media gateway on the called side, and connects the bearer resources of the calling user and the called user.

11. The method of claim 1 or 2, wherein

The message between the called UE and the ICCF is transmitted in the CS domain through the bearer control path, that is, through the visited mobile switching center VMSC, the media gateway control function MGCF, and the call session control function CSCF; between the called UE and the ICCF The message is transmitted in the PS domain through the session control path, that is, through the CSCF.