CN100352295C

CN100352295C - Method for realizing IP multi media sub-system conversation falling to circuit switching call

Info

Publication number: CN100352295C
Application number: CNB2005100026182A
Authority: CN
Inventors: 朱东铭
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2005-01-24
Filing date: 2005-01-24
Publication date: 2007-11-28
Anticipated expiration: 2025-01-24
Also published as: CN1812601A

Abstract

The present invention discloses a method for an IP multimedia subsystem session to fall back on a circuit switching call, which has the steps: an IMS session direction changing instruction and a CS domain addressing number which are returned from a called terminal to a calling terminal when an IMS session falls back on a circuit switching (CS) network are determined according to an IMS session establishing request of the calling terminal; after receiving the direction changing instruction, the calling terminal releases the IMS session requested to be established, and initiates a new IMS session request to the called terminal according to the instruction. An IMS network relevant to a calling side transfers the new IMS session request to an IMS/CS gateway according to the CS domain addressing number, and the gateway maps the new IMS session request into the CS call; the CS call is transferred to the called terminal through the CS network relevant to a called side, and the called terminal interacts with the calling terminal, the IMS network of the calling terminal and an intercommunication gateway of the calling terminal through the CS network and establishes a CS and IMS intercommunication session.

Description

The implementation method of IP Multimedia System conversation falling back to circuit switching call

Technical field

The present invention relates to synthetic circuit exchange carrying and IP Multimedia System (CSI) service technique in the 3G (Third Generation) Moblie network, relate in particular to and wherein IP Multimedia System (IMS) session is fallen back to the implementation method that circuit switching (CS) is called out.

Background technology

Development along with mobile communication technology, people no longer are satisfied with single voice communication mode, and multimedia communication mode that need be brand-new, this multimedia communication is not only simple video and audio communication, also comprise instant message, with the business that browses the location, business such as collaborative work and Streaming Media, particularly new traffic mode and traditional voice merge.

Trend based on Internet and communication network fusion, each standardization body has proposed the notion of next generation network, the IP Multimedia System (IMS) of the all-IP business network framework that 3GPP introduces on the packet carrying network basis, target be according to personalized user data, the shielding user mode access and control professional ability degree of opening multimedia communication experiences is provided.

Among the IMS main functional entity comprise functions such as control user registration, session control controlling call entity CSCF, provide miscellaneous service logic control function application server AS, manage the home subscriber server HSS of user contracting data concentratedly, and be used to realize the MGCF/IMS medium gateway function (MGCF/IM-MGW) with the circuit switching net interconnecting.The user is by current location agent node P-CSCF access IMS, and session and professional triggering control reach with the business control of AS and then finished by the home domain service node S-CSCF of its registered place alternately; IMS adopts initial session protocol (Session Initiation Protocol) as the mutual signaling of application layer.IMS finishes intercommunication with Circuit Switching Network (PSTN or PLMN CS) by Interworking gateway MGCF/IM-MGW, wherein, MGCF realizes the mutual of IMS core chain of command, support protocol interaction and the call intercommunication of ISUP/BICC and SIP, finish and the TDM of Circuit Switching Network carrying and IMS territory user's face width arrowband bearing interconnection and necessary encoding and decoding conversion by H.248 controlling IM-MGW.

The tradition communication network is divided into circuit switching (CS) territory and packet switching (PS) territory, finishes circuit-switched service (comprising speech business, circuit type data service, fax etc.) and Packet data service respectively.The IMS business is made up of control section and media content portion, and control section is the IMS Signalling exchange between IMS terminal and the IMS territory network entity, and the IMS business is controlled, and media content portion is various content media streams such as image, voice-and-data.IMS signaling and Media Stream all pass through the carrying of PS territory.Different (CS is the exclusive resource type because CS and PS are for the processing of Internet resources, PS then is the shared resource type), so for the demanding business of real-time, as speech business, realize to descend to some extent with IMS, may not satisfy operator and user's business demand than the Quality of Service of realizing with CS.For this reason, the 3GPP of International Standards Organization proposes CS is carried the CSI service (Combining CS Bearers with IMS) that combines with IMS, its logic diagram as shown in Figure 1, multimedia service is undertaken by the mode that PS carrying and CS carrying combine,, still carry by CS with the demanding speech business of real-time, the less demanding business of other real-time, as picture, messaging service etc., then by the PS carrying, IMS finishes unified control.

3GPPTR 23.899 is about the technical standard of CSI service among the 3GPP, the essential a series of requirements satisfied of CSI implementation and several fundamental modes of alternative have been provided in this standard, wherein: the situation that carrying is set up according to CS is divided into end-to-end pattern and is held gateway mode, position according to the logic entity of control CS carrying foundation in the IMS business is divided into terminal control and two kinds of different modes of network control again.The logic diagram of holding gateway/mode control terminal as shown in Figure 2, wherein:

A, the CSI terminal that possesses the CSI controlled function are being judged according to certain condition and to be triggered CSI service logic (1) with the IMS session of end subscriber being set up in the process;

B, the CSI terminal that possesses the CSI controlled function are initiated to the circuit domain call of this terminal IMS part, change IMS over to through the CS-IMS gateway, set up E2G CS carrying and obtain the port information (2) that gateway is reserved in this process;

C, possess the CSI controlled function the CSI terminal with 3PCC (third party call control) mode control to end subscriber set up with gateway reservation port between mutual (1,2) of corresponding Media Stream.

In the called flow under the mode control terminal, the CSI terminal that request message will at first be routed to the above-mentioned CSI of possessing controlled function is set up in the IMS session, could determine whether trigger CSI service.

In the called flow under the mode control terminal, because the CSI terminal that request message will at first be routed to the above-mentioned CSI of possessing controlled function is set up in the IMS session, could determine whether trigger CSI service, simultaneously as mentioned above, CSI service need the Radio Access Network support of terminal and the current access of terminal keep simultaneously CS and PS eat dishes without rice or wine be connected, therefore, receiving the IMS session when the CSI terminal that possesses the CSI controlled function sets up request and wishes to use the certain service quality (QoS) of CSI service acquisition, but find that present access subzone does not possess when keeping CS with ability that PS eats dishes without rice or wine to be connected simultaneously, just needs that CS is fallen back in this time session and calls out.In this case, how to realize that the IMS session falls back to CS and call out and to become industry problem anxious to be solved at present.

Summary of the invention

The invention provides a kind of implementation method of IP Multimedia System conversation falling back to circuit switching call, so that in the called flow of holding gateway/mode control terminal CSI service, this time IMS/CSI session can not fallen back to CS when keeping CS simultaneously and call out with reasons such as ability that PS eats dishes without rice or wine to be connected because of present access subzone does not possess.

A kind of implementation method of IP Multimedia System conversation falling back to circuit switching call, the synthetic circuit exchange carrying and IP Multimedia System (CSI) business that are used for holding gateway/mode control terminal; This method comprises the steps:

A, determine whether circuit switching (CS) network is fallen back in this IMS session according to the IMS session of the calling terminal request of setting up, if then carry out step B, otherwise terminal called by relevant IMS network and caller alternately and set up the IMS session;

B, terminal called return IMS session changed course indication to described calling terminal, and carry the addressing number of terminal called in the CS territory, and this CS territory addressing number has indication IMS network and forwards the IMS session to ability that the CS network continues;

C, described calling terminal are receiving the IMS session that described changed course indication back release request is set up, and are initiating new IMS conversation request with described addressing number;

D, gateway receive that it being mapped as CS after the described new IMS conversation request that the relevant network based described CS of the IMS territory of Calling Side addressing number forwards calls out, to terminal called, terminal called by this CS network and described calling terminal alternately and set up the IMS session by the relevant CS network delivery of callee side.

A, terminal called determine whether circuit switching (CS) network is fallen back in this IMS session according to the IMS session request of setting up of calling terminal, if then carry out step B, otherwise terminal called by relevant IMS network and calling terminal alternately and set up the IMS session;

B, terminal called return the IMS session to described calling terminal and discharge indication, and utilizing the CS territory addressing number of calling terminal to initiate the CS setup requests to calling terminal by this side CS network, this CS territory addressing number has indication CS network and transfers the call to the ability that the IMS network continues;

C, gateway are received that the relevant network based described CS of the CS territory of callee side addressing number is transmitted after the described CS setup requests of coming and it are mapped as the IMS network of new IMS conversation request by Calling Side and are sent to calling terminal;

D, calling terminal discharge local terminal according to described release indication had before asked the IMS session of setting up, and according to described new IMS conversation request and described terminal called alternately and set up the IMS session.

The invention provides a terminal under gateway/mode control terminal in the CSI scheme, the CSI terminal of the called CSI of possessing controlled function because of the limitation of conditions or user intention the implementation that CS calls out is fallen back in current I MS/CSI session, thereby further perfect terminal CSI scheme under gateway/mode control terminal has improved the applicability of scheme and has improved the CSI service user experience, strengthened the CSI service characteristic.

Description of drawings

The CSI service schematic diagram that Fig. 1 combines with IMS for the CS carrying;

Fig. 2 is for holding gateway/mode control terminal logic diagram;

Fig. 3, Fig. 4 fall back to the flow chart that CS calls out for the present invention realizes the IMS session.

Embodiment

The present invention by send the call re-direction indication to calling terminal, initiates IMS again by calling terminal and calls out after terminal called determines that according to the IMS session of the calling terminal request of setting up this IMS session fallen back to circuit switching (CS) network; Perhaps, terminal called adopts with specific reasons and discharges the IMS session that request is set up, and then initiates mode to this user's calling at CS automatically and realize that the IMS session falls back to CS and call out.The present invention is described in detail below in conjunction with accompanying drawing.

Consult shown in Figure 3ly, initiating the changed course indication by terminal called to calling terminal, to realize that the process that CS calls out is fallen back in the IMS session as follows:

Step 1:IMS terminal A initiates the IMS session of VoIP to the CSI terminal B that use possesses the CSI controlled function, and the IMS session is set up request message through relevant (affiliated and current place) the IMS network incoming terminal B of terminal A, B.

Step 2: the CSI terminal B that possesses the CSI controlled function sets up relevant indication triggering CSI service logic in the request according to session, comprises in the CSI service logic that triggers and checks this side CSI service condition and determine whether that with the user interactions wish CS is fallen back in the IMS session of current triggering CSI service to be called out.Can't satisfy the next IMS session of situation in the professional required condition of current C SI and fall back to the CS calling, or select decision that CS is fallen back in the IMS session of current triggering CSI service by user intention and call out current triggering CSI service; Otherwise carry out IMS session (not going out among the figure) mutual and that set up the application CSI service by prior art.Trigger the CSI service logic basis for estimation can but be not limited to calling terminal A and set up in the IMS session and advise mutual medium type in the request message, as be judged as in voip conversation or the mutual medium and have the media portion that real-time is had relatively high expectations.

The inspection of this side CSI service condition can include but not limited to the ability that the wireless access network of current access keeps CS/PS to eat dishes without rice or wine to connect simultaneously.The CSI service logic also can comprise the user intention affirmation, and user intention is confirmed to adopt but is not limited to following mode:

(1) carries out real-time interaction by particular user interface on the terminal (as popup menu) with the user;

(2) by the user in advance being provided with automatically on terminal determine.

Step 3: after determining to fall after rise the CS calling, the CSI terminal B that possesses the CSI controlled function responds the indication of IMS call re-direction to terminal A, wherein carried terminal B calls out the E.164 number that addressing is used at CS, and terminal A responds changed course and confirms to discharge the IMS session that this request is set up.

The E.164 number that described terminal B uses in CS calling addressing should be able to have the relevant IMS network of indicating terminal A and forward calling to ability that CS continues, can be the MSISDN (Mobile Subscriber International ISDN number) that terminal B contracts at CS, also can constitute by this number interpolation particular prefix or special identifier.

Step 4: terminal A initiates new IMS session according to IMS session changed course indication and sets up request, and the purpose that session is set up is designated the E.164 number that terminal B provides in the changed course indication.

Relevant network based this number analysis of the IMS result of step 5: terminal A transfers session to CS and continues and select Interworking gateway, request message is set up in session be forwarded to this gateway.

Step 6: described Interworking gateway is carried out the IMS/CS intercommunication then and is handled, and finishes the route analysis of terminal B at CS by CS standard handling process, through the CS network CS setup requests is sent to terminal B.Simultaneously, this Interworking gateway and party A-subscriber finish the SDP negotiation of IMS session section by the relevant IMS network of party A-subscriber.

If in step 3, the E.164 number that terminal B returns has adopted by Mobile Subscriber International ISDN Number and has added particular prefix or special identifier constituted mode, then can be finished the deduction of this prefix or sign by gateway, adopts MSISDN to finish interaction process with the CS network then; If having adopted by Mobile Subscriber International ISDN Number, the E.164 number that terminal B returns adds particular prefix or special identifier constituted mode, gateway also can or identify according to this prefix under the situation of finishing this prefix or sign deduction judges that this time calling falls calling after rise for CSI service is relevant, thereby in the CS call control signalling, add special indication, make CS network or user B to carry out the relevant special processing that falls calling after rise of CSI service according to this indication.

After step 7, terminal B receive the CS call request, finish the CS call setup with corresponding CS network interaction and handle, successively return CS user's ring, CS user answer message to Interworking gateway, the CS that sets up between user B and Interworking gateway calls out; Interworking gateway is carried out the IMS/CS intercommunication and is handled, said process is mapped as the IMS session sets up respective process, successively return IMS user's ring and IMS user answer through the relevant IMS network of party A-subscriber to the party A-subscriber, user A returns IMS and replys and confirm to set up the IMS session between back and gateway.

The special indication that the network based above-mentioned gateway of CS adds, can carry out but be not limited to following special processing:

(1) special charging is handled: as according to this indication deduction and exemption portion C S telephone expenses, need charge system to carry out the function corresponding expansion;

(2) service conflict is handled: as evade portion C S territory supplementary service according to this indication, as preceding commentaries on classics, calling locking and intelligent trigger etc., need the CS network to carry out the function corresponding expansion.

Terminal B is according to the special indication that above-mentioned gateway adds, and can carry out but is not limited to following special processing:

(1) discerning this time calling is that relevant falling the after rise of CSI service called out, thereby is prompted to the user by modes such as popup menu, special bell sounds;

(2) discern this time calling and fall calling for CSI service is relevant after rise and be prompted to the user, under user's control, enable processing such as Call Deflexion then.

Consult shown in Figure 4ly, initiate to discharge indication and initiatively initiate CS and call out that to realize that the process that CS calls out is fallen back in the IMS session as follows to calling terminal to calling terminal by terminal called:

Step 20-step 21 is identical with above-mentioned steps 1-step 2, repeats no more.

Step 22: after determining to fall after rise the CS calling, terminal B responds the IMS calling to terminal A and discharges indication; Terminal A responds to discharge and confirms to discharge the IMS session that this request is set up.

The Mobile Subscriber International ISDN Number that indication of portability CSI service and terminal B use at CS in discharging indication, terminal A writes down this Mobile Subscriber International ISDN Number.

Step 23: terminal B makes a call to set up to terminal A at CS then and asks, and called number wherein is for pointing to the E.164 number of terminal A.This E.164 number have the relevant CS network of indicating terminal B and forward calling to ability that IMS continues, can be terminal A at the signatory MSISDN (Mobile Subscriber International ISDN number) of CS, also can add particular prefix and constitute by this number.

Terminal B can obtain to point to the E.164 number of terminal A in the following manner: in calling out according to IMS in the From header field IMS sign of terminal A derive (depending on the particular network numbering plan) or obtain according to IMS sign and the directory information of terminal A.

The special indication that terminal B also can add in the CS call setup request message of initiating makes CS network or IMS/CS Interworking gateway to carry out the relevant special processing that falls callback after rise of CSI service according to this indication.

The relevant network based called number analysis result of CS of step 24: terminal B routes the call to the IMS/CS Interworking gateway.

If in step 23, terminal B adds the method that prefix constitutes called number or directly adds special indication before the CS call setup request message of initiating has been taked user's Mobile Subscriber International ISDN Number at terminal A, the then special indication in call setup request message, added of relevant network based described E.164 particular prefix that number added of CS of terminal B or terminal B, can carry out but be not limited to following special processing:

(2) service conflict is handled: as evade the Calling Side supplementary service of portion C S territory according to this indication, as calling out locking, closed user group and intelligent trigger etc., can evade the mechanism processing of above-mentioned Business Processing according to existing urgent call of CS or special service call.

Step 25: finish by the IMS/CS Interworking gateway and to comprise that the IMS/CS intercommunication handles, finish the SDP negotiation of IMS session section by the relevant IMS network of terminal A, final foundation and the IMS session of terminal A with terminal A.

If in step 23, terminal B adds the method that prefix constitutes called number or directly adds special indication before the CS call setup request message of initiating has been taked user's Mobile Subscriber International ISDN Number at terminal A, then the IMS/CS Interworking gateway is according to the special indication that the described E.164 particular prefix that number added or user B add in call setup request message, can carry out but be not limited to set up in the IMS session of being shone upon adding special indication in the request message.

After step 26: terminal A receives IMS session foundation request, finish the IMS session alternately by its relevant IMS network and IMS/CS Interworking gateway and set up processing, successively return IMS user's ring, IMS user answer message to Interworking gateway, gateway returns IMS and replys the IMS that sets up after the affirmation between terminal A and Interworking gateway and call out; Interworking gateway is carried out the IMS/CS intercommunication and is handled, and said process is mapped as the CS session sets up respective process, successively returns CS user's ring and CS user answer through the relevant CS network of terminal B to terminal B, sets up the CS session with terminal B.

Adopted the processing of the MSISDN that carries and write down terminal B in step 22, or step 25IMS/CS gateway has carried out setting up under the situation of the processing of adding special indication in the request in the IMS session, if terminal A determines that the MSISDN that the IMS session is set up in the From header field in the request message is the Mobile Subscriber International ISDN Number that writes down previously, or, can carry out but be not limited to following special processing according to the special indication that described IMS/CS Interworking gateway adds in the IMS session request of setting up:

(1) discerns this time and call out, thereby be prompted to the user by modes such as popup menu, special bell sounds to CSI service falls callback after rise;

(2) discern this time and call out, thereby set up release user ring process in the process in session to CSI service falls callback after rise.

Obviously, those skilled in the art can carry out various changes and modification to the present invention and not break away from the spirit and scope of the present invention.Like this, if of the present invention these are revised and modification belongs within the scope of claim of the present invention and equivalent technologies thereof, then the present invention also is intended to comprise these changes and modification interior.

Claims

1, the implementation method that circuit switching (CS) is called out is fallen back in a kind of IP Multimedia System IMS session, is used for holding the synthetic circuit exchange carrying and IP Multimedia System CSI service of gateway/mode control terminal; It is characterized in that this method comprises the steps:

A, terminal called judge whether the CS network is fallen back in this IMS session according to the IMS session request of setting up of calling terminal, if then carry out step B, otherwise terminal called by relevant IMS network and caller alternately and set up the IMS session;

B, terminal called return IMS session changed course indication to described calling terminal, and carry terminal called at the CS territory in CS territory addressing number, and this CS territory addressing number has indication IMS network and forwards the IMS session to ability that the CS network continues;

C, described calling terminal are receiving the IMS session that the previous request of described changed course indication back release is set up, and are initiating new IMS conversation request with described addressing number;

2, implementation method as claimed in claim 1 is characterized in that, in the steps A, triggers terminal called and judges whether that the condition that the CS network is fallen back in the IMS session is comprised that calling terminal is set up in the IMS session advises mutual medium type in the request message.

3, implementation method as claimed in claim 2 is characterized in that, terminal called determines whether that by the CSI service condition that detects this side CS is fallen back in the IMS session to be called out, and perhaps determines whether that by the user CS is fallen back in the IMS session to be called out.

4, implementation method as claimed in claim 3 is characterized in that, described side CSI service condition comprises: the ability that wireless access network while holding circuit exchange/packet switching CS/PS eats dishes without rice or wine to connect.

5, implementation method as claimed in claim 3, it is characterized in that, determine whether that by the user mode that CS calls out is fallen back in the IMS session to be comprised: terminal called determines for the user by particular user interface is provided, or according to the user in advance being provided with automatically on terminal determine.

6, implementation method as claimed in claim 1 is characterized in that, described CS territory addressing number is the Mobile Subscriber International ISDN number MSISDN that the user contracts at CS, perhaps adds the number of particular prefix or special identifier formation for this MSISDN.

7, implementation method as claimed in claim 6, it is characterized in that, add particular prefix or special identifier when constituting when described CS territory addressing number adopts MSISDN, deduct by the IMS/CS gateway in the network and adopt after this prefix or the special identifier MSISDN to finish interaction process with the CS network.

8, implementation method as claimed in claim 6, it is characterized in that, when described CS territory addressing number adopts MSISDN to add particular prefix or special identifier formation, gateway adds special indication according to described prefix or special identifier in the CS call control signalling, make CS network or terminal called carry out the relevant special processing that falls calling after rise of CSI service according to this indication.

9, implementation method as claimed in claim 8 is characterized in that, the special processing that described CS network carries out comprises special charging processing and service conflict processing.

10, implementation method as claimed in claim 8 is characterized in that, the special processing that described terminal called carries out comprises the prompting user, or enables Call Deflexion behind the prompting user under user's control and handle.

11, a kind of implementation method of IP Multimedia System IMS conversation falling back to circuit switching call, the synthetic circuit exchange carrying and IP Multimedia System CSI service that are used for holding gateway/mode control terminal; It is characterized in that this method comprises the steps:

A, terminal called determine whether the circuit switching (CS) network is fallen back in this IMS session according to the IMS session request of setting up of calling terminal, if then carry out step B, otherwise terminal called by relevant IMS network and calling terminal alternately and set up the IMS session;

12, implementation method as claimed in claim 11 is characterized in that, in the steps A, triggers terminal called and judges whether that the condition that the CS network is fallen back in the IMS session is comprised that calling terminal is set up in the IMS session advises mutual medium type in the request message.

13, implementation method as claimed in claim 12 is characterized in that, terminal called determines whether that by the CSI service condition that detects this side CS is fallen back in the IMS session to be called out, and perhaps determines whether that by the user CS is fallen back in the IMS session to be called out.

14, implementation method as claimed in claim 13 is characterized in that, described side CSI service condition comprises the ability that wireless access network while holding circuit exchange/packet switching CS/PS eats dishes without rice or wine to connect.

15, implementation method as claimed in claim 13 is characterized in that, the mode of being determined by the user comprises: terminal called determines for the user by particular user interface is provided, or according to the user in advance being provided with automatically on terminal determine.

16, implementation method as claimed in claim 11, it is characterized in that, carry indication CS network in the described CS setup requests or/and the CS/IMS Interworking gateway carries out the special indication of special processing to calling, the CS network is or/and the CS/IMS Interworking gateway carries out special processing according to this special indication to calling.

17, implementation method as claimed in claim 11 is characterized in that; Described CS territory addressing number is that the user adds the particular prefix formation at the Mobile Subscriber International ISDN number of CS network contraction, and the CS network is or/and the CS/IMS Interworking gateway carries out special processing according to this prefix to calling.

18, as claim 16 or 17 described implementation methods, it is characterized in that, the CS network or/and the special processing that the particular prefix that the CS/IMS Interworking gateway adds according to described special indication or described MSISDN carries out comprise: special charging processing, service conflict are handled and add special indication in the IMS sessions, described special indication be used to indicate calling terminal to CSI service callback IMS session carry out special processing.

19, implementation method as claimed in claim 11, it is characterized in that, in described release indication, carry the Mobile Subscriber International ISDN Number of CSI service indication and terminal called, when sending the terminal that discharges indication and be same terminal, special processing is carried out in session to calling terminal to this time CSI service callback IMS in the terminal of receiving the follow-up CSI service callback IMS session of initiating at CS of terminal called and determining described IMS conversation request.

20, implementation method as claimed in claim 18 is characterized in that, the special processing that calling terminal carries out is set up release user ring in the process in session after comprising prompting user and prompting user.

21, implementation method as claimed in claim 19 is characterized in that, the special processing that calling terminal carries out is set up release user ring in the process in session after comprising prompting user and prompting user.

22, implementation method as claimed in claim 11, it is characterized in that, the IMS sign of calling terminal was derived the CS territory addressing number of calling terminal during terminal called was called out according to IMS, or according to the IMS sign of calling terminal and the CS territory addressing number of directory information acquisition calling terminal.