CN102104848A

CN102104848A - Dual-mode single-standby voice service continuity realization method and Internet protocol (IP) multimedia subsystem

Info

Publication number: CN102104848A
Application number: CN2009102425359A
Authority: CN
Inventors: 姜怡; 吴宁
Original assignee: China Mobile Communications Group Co Ltd
Current assignee: China Mobile Communications Group Co Ltd
Priority date: 2009-12-16
Filing date: 2009-12-16
Publication date: 2011-06-22
Anticipated expiration: 2029-12-16
Also published as: CN102104848B

Abstract

The invention provides a dual-mode single-standby voice service continuity realization method and an Internet protocol (IP) multimedia subsystem. The method comprises the following steps that: A, when local user equipment issues a session request from a long-term evolution (LTE) network, a service continuity control application server (SCC AS) in an information management system (IMS) anchors media links of the local user equipment and opposite user equipment onto a media functional processing entity in the IMS; and B, after the local user equipment is switched from evolved universal terrestrial radio access network (E-UTRAN) access to Gsm edge radio access network (GERAN)/terrestrial radio access network (UTRAN) access, the SCC AS updates the media link of the local user equipment to be the media link between a mobile switching center (MSC) Server and the media functional processing entity. By the method and the subsystem, the interruption time of a media plane in the switching of the user equipment from the LTE network to a 2G/3G network can be shortened, and user experiences are improved.

Description

The implementation method of double-mode single-standby voice business continuity and IP Multimedia System

Technical field

The present invention relates to wireless communication field, the implementation method of particularly a kind of double-mode single-standby voice business continuity (SRVCC) and IP Multimedia System (IMS).

Background technology

First stage of construction at Long Term Evolution (LTE) network, its signal cover is limited, when the user is using the LTE network to carry out in the voice call process, move to the LTE network signal a little less than, but in the local time that the 2G/3G network signal covering preferably, in order to keep the continuity of speech business, voice call need be switched to the 2G/3G network by the LTE network.Owing to does not also have at present and can adhere to the also terminal of transceive data simultaneously, so the voice business continuity between LTE network and the 2G/3G network all is based on the double-mode single-standby mode at LTE network and 2G/3G network.

Third generation affiliate (3GPP) has made the voice business continuity scheme of double-mode single-standby mode at present, i.e. the SRVCC scheme that proposes among the 3GPP TS 23.216.Fig. 1 is for switching to speech business the Access Network part control flow chart of 2G/3G network from the LTE network in the existing SRVCC scheme, wherein, the Access Network of LTE network is called the universal mobile telecommunications system land radio access web (E-UTRAN) of evolution, the Access Network of 2G network is called GSM enhanced data rates wireless access network (GERAN), the Access Network of 3G network is called universal land radio access web (UTRAN), with reference to Fig. 1, this control flow mainly may further comprise the steps:

Step 101: local terminal terminal (UE) sends measurement report to source E-UTRAN.

Step 102: based on the measurement report of UE, E-UTRAN decision in source triggers a switching to the SRVCC of GERAN.

Step 103: source E-UTRAN sends handoff request message to source Mobility Management Entity (MME).

Step 104: after source MME receives handoff request message, switching indication based on SRVCC, separate original voice bearer, and one of the initialization handoff procedure to the packet domain of Mobile Switching Center Server (MSC Server) to circuit domain (PS to CS) is to obtain new voice bearer.

Step 105: source MME sends the request message of the PS territory of a SRVCC to the CS territory to MSC Server.

Step 106:MSC Server is by the handoff request between the MSC that initiates a CS territory to a preparation of purpose MSC transmission handoff request message.

Step 107: purpose MSC is by coming to carry out resource allocation for purpose BSS with purpose base station sub-system (BSS) exchange handoff request/acknowledge message.

Step 108: purpose MSC sends to MSC Server and prepares switching response message.

Step 109: between the media gateway (MGW) of purpose MSC and MSC Server distribution, set up circuit and connect, for example, setting up described circuit by the initial address message (IAM) of integrated digital service-user part (ISUP) signaling with Address Complete Message (ACM) is connected.

Step 110:MSC Server comes initiation session to shift by the session forwarding number (STN-SR) that uses SRVCC, for example send the IAM message of the ISUP that carries STN-SR by the double-mode single-standby voice business continuity application server (SCC AS) in the IMS territory, the IMS business continuance process of a standard is carried out in application.

Step 111: in the implementation that session is shifted, distant end media will be updated to the Session Description Protocol (SDP) that CS inserts side, and the descending VoIP data flow is switched to CS and inserts on the purpose MSC of side, and the media resource of source IMS access side is released.This part process is independent of subsequent process, will describe in detail in Fig. 2.

Step 112:MSC Server sends the response message of the PS territory of SRVCC to the CS territory to source MME.

Step 113: source MME sends handover command messages to source E-UTRAN.

Step 114: source E-UTRAN sends the instruction message that switches from E-UTRAN to local terminal UE.

Step 115: local terminal UE switches to GERAN from source E-UTRAN.

Step 116: on purpose BSS, carry out change detection, detect successfully after, Access Network partly switches to be finished.

Fig. 2 switches to 2G/3G server mesh portions control flow chart with speech business from the LTE network in the existing SRVCC scheme, and with reference to Fig. 2, this control flow mainly may further comprise the steps:

Step 201:MSC Server carries out the message route by STN-SR, and IAM message is sent to MGCF entity (MGCF), carries medium face address and the port of purpose MSC in the message.

Step 202:MGCF is invitation (INVITE) message of conversation initialized protocol (SIP) with the IAM message maps, and SDP wherein carries the media information of purpose MSC, and message is sent to query call conversation control function (I-CSCF).

Step 203:I-CSCF is transmitted to service call conversation control function (S-CSCF) with INVITE.

Step 204:S-CSCF triggers by business INVITE is transmitted to SCC AS.

Step 205:SCC AS judges terminal according to STN-SR the SRVCC switching has taken place, therefore more new technological process of distant end media is initiated in decision, SCC AS generates the SDP of new far-end UE according to the SDP in the INVITE, and sends to S-CSCF by heavy invitation (reINVITE) message.

Step 206:S-CSCF sends to this reINVITE message the Proxy Call Session Control Function (P-CSCF) at far-end UE place.

Step 207:P-CSCF sends to far-end UE with this reINVITE message.

Step 208: far-end UE upgrades local medium (opposite end SDP is updated to new SDP) according to the new SDP that receives, new address, opposite end that beginning is carried in new SDP and port send media data, return the 200OK response message simultaneously.

Step 209～213:200OK response message is routed to MGCF.

Step 214:MGCF is that ANM sends to MSC Server with the 200OK message maps, and distant end media is upgraded and finished.

Fig. 3 can see that among the existing SRVCC speech business being switched to the signaling of 2G/3G network front and back and the variation schematic diagram of medium from the LTE network signaling is anchored on SCC AS signaling, and medium then are end-to-end, do not have anchor point.

From the above description as can be known, existing SRVCC scheme needs the media link of the far-end UE that more converses the first month of the lunar year and switching terminal, promptly by original in the LTE media link of gateway/packet data network gateway (ServingGW/PDN GW) be updated to the media link of the IP multimedia gateway (IM-MGW) among the IMS.In order to realize the renewal of this media link, the signaling aspect also needs the SCC AS in the IMS core net to be initiated to the request of the session updates of far-end UE.Before finishing in the distant end media renewal, the user can't receive voice at the 2G/3G network, so the media break time that switching causes is depended on distant end media renewal required time substantially.Yet, because the uncertainty of UE on-position, for example the user may be in the roaming, at this moment the renewal of the time delay of the session updates signaling from SCC AS to far-end UE and media link may need the long time, like this after terminal switches to the 2G/3G network from the LTE network, can't receive the medium of opposite end UE within a certain period of time, thereby cause the user can experience the sound interruption of a period of time, user experience is relatively poor.

Summary of the invention

Technical problem to be solved by this invention provides a kind of implementation method and IP Multimedia System of double-mode single-standby voice business continuity, to shorten the break period of terminal medium face when the LTE network switches to the 2G/3G network, improves user experience.

For solving the problems of the technologies described above, it is as follows to the invention provides technical scheme:

A kind of implementation method of double-mode single-standby voice business continuity comprises the steps:

A, when the local terminal terminal initiates a session request from the LTE network, the SCC AS among the IMS all is anchored on the media link of local terminal terminal and distant terminal on the media function processing entities among the described IMS;

B, the local terminal terminal insert from E-UTRAN switch to insert from GERAN/UTRAN after, described SCC AS is updated to media link between MSC Server and the described media function processing entities with the media link of local terminal terminal.

Described steps A specifically comprises:

The local terminal terminal is passed through the LTE network at the IMS network registry, and initiates a session request;

Serving GW sends to initial INVITE message on the SCC AS according to described conversation request;

Described SCC AS makes amendment to the SDP data in the initial INVITE message, is addresses distributed and port on the medium processing capacity entity with the address and the port modifications of wherein medium face;

Distance terminal returns its SDP data by response message, and described SCC AS makes amendment to the SDP data in the response message, is another address and the port that distributes on the described medium processing capacity entity with the address and the port modifications of wherein medium face.

Described step B specifically comprises:

SCC AS receives the INVITE that carries STN-SR that S-CSCF sends;

SCC AS determines that according to the STN-SR in the described INVITE switching has taken place the local terminal terminal, control medium processing capacity entity upgrades the media link of local terminal terminal, and promptly new address in the SDP of described INVITE data and port are transmitted media data packet.

A kind of IP Multimedia System comprises SCC AS and media function processing entities, and described SCC AS is used for:

When the local terminal terminal initiates a session request from the LTE network, the media link of local terminal terminal and distant terminal all is anchored on the described media function processing entities;

The local terminal terminal insert from E-UTRAN switch to insert from GERAN/UTRAN after, the media link of local terminal terminal is updated to media link between MSC Server and the described media function processing entities.

Described SCC AS is further used for:

SDP data in the initial INVITE message that Serving GW is sent are made amendment, and are addresses distributed and port on the medium processing capacity entity with the address and the port modifications of wherein medium face;

The SDP data of answering in the message that distance terminal returns are made amendment, and are another address and the port that distributes on the described medium processing capacity entity with the address and the port modifications of wherein medium face.

Described SCC AS is further used for:

Receive the INVITE that carries STN-SR that S-CSCF sends;

Determine that according to the STN-SR in the described INVITE switching has taken place the local terminal terminal, control medium processing capacity entity upgrades the media link of local terminal terminal, and promptly new address in the SDP of described INVITE data and port are transmitted media data packet.

In the technical scheme of the embodiment of the invention, when the local terminal terminal initiates a session request from the LTE network, SCC AS among the IMS all is anchored on the media link of local terminal terminal and distant terminal on the media function processing entities among the described IMS, with the speech business of local terminal terminal when the LTE network switches to the 2G/3G network, only need to upgrade the media link of local terminal terminal, and do not need to upgrade the media link of distance terminal.By avoiding upgrading the media link of distance terminal, can save signaling consumption, shorten the break period of medium face when switching, thereby improve user experience.

Description of drawings

Fig. 1 is for switching to speech business the Access Network part control flow chart of 2G/3G network from the LTE network in the existing SRVCC scheme;

Fig. 2 switches to 2G/3G server mesh portions control flow chart with speech business from the LTE network in the existing SRVCC scheme;

Fig. 3 is for switching to the signaling of 2G/3G network front and back and the variation schematic diagram of medium with speech business from the LTE network in the existing SRVCC scheme;

Fig. 4 is the implementation method flow chart of the double-mode single-standby voice business continuity of the embodiment of the invention;

The grappling process flow diagram of media link when Fig. 5 initiates a session request for terminal in the embodiment of the invention;

Fig. 6 switches to 2G/3G server mesh portions control flow chart with speech business from the LTE network in the SRVCC scheme of the embodiment of the invention;

Fig. 7 is for switching to the signaling of 2G/3G network front and back and the variation schematic diagram of medium with speech business from the LTE network in the SRVCC scheme of the embodiment of the invention.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, describe the present invention below in conjunction with the accompanying drawings and the specific embodiments.

The embodiment of the invention proposes a kind of improvement project that is used for speech business is switched to from the LTE networking SRVCC of 2G/3G network, mainly be to improve at the flow process of core net control section, by avoiding upgrading the media link of far-end UE, save signaling consumption, shorten the break period of medium face when switching, thereby improve user experience.

For guaranteeing the continuity of session, terminal is in the LTE network during initiation session, the control signaling of session is anchored on the application server SCC AS into this Terminal Service, SCC AS is as the anchor point of user conversation signaling, carry out the renewal of session switching controls and media link, help terminal to carry out the seamless switching of LTE network to the 2G/3G network.

Because SCC AS also possesses media control function, in embodiments of the present invention, utilize the media control function of SCC AS, when session is initiated, in the transmission path of medium, insert a medium processing capacity entity, as the anchor point of terminal session medium, Media Stream is received and handles.

Fig. 4 is the implementation method flow chart of the double-mode single-standby voice business continuity of the embodiment of the invention, and with reference to Fig. 4, described method mainly comprises the steps:

Step 401: when the local terminal terminal initiated a session request from the LTE network, the SCC AS among the IMS all was anchored on the media link of local terminal terminal and distant terminal on the media function processing entities among the described IMS;

Step 402: the local terminal terminal insert from E-UTRAN switch to insert from GERAN/UTRAN after, described SCC AS is updated to media link between MSC SERVER and the described media function processing entities with the media link of local terminal terminal.

Medium processing capacity entity in the embodiment of the invention is positioned at the ownership IMS network of terminal, possesses media data reception/forwarding capability and medium code/decode type translation function.All Media Streams of local terminal terminal session will at first send to medium processing capacity entity, be transmitted to distant terminal by medium processing capacity entity then, the Media Stream of distant terminal also sends to medium processing capacity entity simultaneously, is transmitted to the local terminal terminal by medium processing capacity entity.

Medium processing capacity entity can carry out media negotiation in switching, determine medium code/decode type with the 2G/3G network interworking, and media stream code/decode format changed, terminal can use different media stream code/decode types and distance terminal to carry out the intercommunication of medium face after switching to the 2G/3G network like this.

Medium processing capacity entity can be the physical equipment that is provided with separately, also can utilize existing gateway device in the IMS network.

The grappling process flow diagram of Fig. 5 media link when terminal being initiated a session request in the embodiment of the invention, with reference to Fig. 5, it mainly comprises the steps:

Step 501: the local terminal terminal is passed through the LTE network at the IMS network registry, and initiates a session request;

Step 502: the SRVCC business because the user has contracted, Serving GW sends to initial INVITE message on the SCC AS according to described conversation request;

Step 503:SCC AS is as back-to-back user agent (B2BUA), SDP data in the initial INVITE message are made amendment, with the address and the port modifications of wherein medium face is addresses distributed and port on the medium processing capacity entity, and carries out subsequent media and consult;

Step 504: distance terminal returns its SDP data by response message, SCC AS makes amendment to the SDP data in the response message, with the address and the port modifications of wherein medium face is another address and the port that distributes on the medium processing capacity entity, and carries out subsequent media and consult;

Step 505: after media negotiation is finished, the media link of local terminal terminal and distant terminal all has been anchored on the medium processing capacity entity, during normal talking, the media data packet of both sides' terminal all sends to medium processing capacity entity, is transmitted by medium processing capacity entity.

In the embodiment of the invention, speech business is not compared with prior art changed from the control flow that the LTE network switches to the Access Network part of 2G/3G network, and variation has taken place in the control flow of core net part.

Fig. 6 switches to 2G/3G server mesh portions control flow chart with speech business from the LTE network in the SRVCC scheme of the embodiment of the invention, and with reference to Fig. 6, it mainly comprises the steps:

Step 601:MSC Server carries out the message route by STN-SR, and IAM message is sent to interconnection network element MGCF.

Step 602:MGCF is the SIP INVITE with the IAM message maps, and message is sent to I-CSCF.

Step 603:I-CSCF is transmitted to S-CSCF with INVITE.

Step 604:S-CSCF triggers by business INVITE is transmitted to SCC AS.

Therefore step 605:SCC AS judges terminal by STN-SR the SRVCC switching has taken place, and controls medium processing capacity entity the media link of local terminal terminal is upgraded, and promptly new address in the SDP of INVITE data and port are transmitted media data packet.SCC AS does not need to initiate more new technological process of distant end media to distance terminal.

Step 606:SCC AS returns the 200OK response message to S-CSCF.

Step 607:S-CSCF gives I-CSCF with the 200OK forwards.

Step 608:I-CSCF gives MGCF with the 200OK forwards.

Step 609:MGCF is an ANM with the 200OK message maps, sends to MSC Server, and medium upgrade to be finished.

Fig. 7 switches to the signaling of 2G/3G network front and back and the variation schematic diagram of medium for speech business in the SRVCC scheme of the embodiment of the invention from the LTE network.As seen, in embodiments of the present invention, switching flow no longer needs to upgrade the medium of distance terminal, and only needs new media processing capacity entity more to be connected with medium between the local terminal terminal.Because SCC AS and medium processing capacity entity are positioned at the ownership IMS network of the local terminal terminal of initiating switching, the local terminal terminal connects the handover delay that the medium of handover delay much smaller than the local terminal terminal to distant terminal connect to the medium of medium processing capacity entity, simultaneously because medium processing capacity entity is compared the performance advantage of terminal on the medium hand-off process, its medium switching times is also much smaller than medium switching time of distance terminal.Therefore, totally switch the sound interruption time that causes and to significantly reduce.

Should be noted that at last, above embodiment is only unrestricted in order to technical scheme of the present invention to be described, those of ordinary skill in the art is to be understood that, can make amendment or be equal to replacement technical scheme of the present invention, and not breaking away from the spiritual scope of technical solution of the present invention, it all should be encompassed in the middle of the claim scope of the present invention.

Claims

1. the implementation method of a double-mode single-standby voice business continuity is characterized in that, comprises the steps:

A, when the local terminal terminal initiates a session request from Long Term Evolution LTE network, the double-mode single-standby voice business continuity application server SCC AS among the IP Multimedia System IMS all is anchored on the media link of local terminal terminal and distant terminal on the media function processing entities among the described IMS;

B, the local terminal terminal insert from the universal mobile telecommunications system land radio access web E-UTRAN of evolution switch to insert from GSM enhanced data rates wireless access network/universal land radio access web GERAN/UTRAN after, described SCC AS is updated to media link between mobile switching center server MSC Server and the described media function processing entities with the media link of local terminal terminal.

2. the implementation method of double-mode single-standby voice business continuity as claimed in claim 1 is characterized in that, described steps A specifically comprises:

Gateway Serving GW will initially invite INVITE to send on the SCC AS according to described conversation request;

Described SCC AS makes amendment to the Session Description Protocol SDP data in the initial INVITE message, is addresses distributed and port on the medium processing capacity entity with the address and the port modifications of wherein medium face;

3. the implementation method of double-mode single-standby voice business continuity as claimed in claim 1 is characterized in that, described step B specifically comprises:

SCC AS receives the INVITE of the session forwarding number STN-SR that carries SRVCC of service call conversation control function S-CSCF transmission;

4. an IP Multimedia System is characterized in that, comprises SCC AS and media function processing entities, and described SCC AS is used for:

5. IP Multimedia System as claimed in claim 4 is characterized in that, described SCC AS is further used for:

6. IP Multimedia System as claimed in claim 4 is characterized in that, described SCC AS is further used for:

Receive the INVITE that carries STN-SR that S-CSCF sends;