CN103200626A

CN103200626A - Modified reverse-direction one-standby service continuity implementation method and device

Info

Publication number: CN103200626A
Application number: CN2012100010273A
Authority: CN
Inventors: 徐绍华; 谢振华
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2012-01-04
Filing date: 2012-01-04
Publication date: 2013-07-10
Also published as: WO2013102393A1

Abstract

The invention discloses a modified reverse-direction one-standby service continuity implementation method. The modified reverse-direction one-standby service continuity implementation method comprises the following steps of enhancing a mobile switching center (eMSC), obtaining information of a signaling anchor point, switching from a circuit switching domain (CS) to a packet switching domain (PS), assigned by an IP multi-media subsystem (IMS) to a terminal, judging if a signaling channel of a current conversation of the terminal does not include the signaling anchor point, switching from the CS to the PS, assigned by the IMS network to the terminal after the eMSC receives a switching request of switching the terminal from the CS to the PS, and then stopping switching the terminal from the CS to the PS. A device comprises an information acquisition module, a judging module and a processing module. The modified reverse-direction one-standby service continuity implementation method and the device can accelerate a conversation switching process from the CS domain to the PS domain and reduce signaling expenditure at the time of a switching failure.

Description

A kind of improved reverse single standby service continuity implementation method and device

Technical field

The present invention relates to the communications field, relate in particular to reverse single standby service continuity implementation method and device in IP (network interconnection agreement, Internet Protocol the are called for short IP) IP multimedia subsystem, IMS.

Background technology

IP Multimedia System (IP Multimedia Core Network Subsystem, be called for short IMS) be by third generation partner program (3rd Generation Partnership Project, abbreviation 3GPP) a kind of IP-based network framework that proposes, made up an opening and service environment flexibly, support multimedia application, can provide abundant multimedia service for the user.

In the IMS business system, key-course separates with operation layer, and key-course does not provide concrete business, and functions such as necessary triggering, route, charging only are provided to operation layer.Professional triggering and control function are that CSCF (Call Session Control Function is called for short CSCF) is finished in the key-course.CSCF is divided into: Proxy Call Session Control Function (Proxy-CSCF, abbreviation P-CSCF), query call conversation control function (Interrogating-CSCF, be called for short I-CSCF) and service call conversation control function (Serving-CSCF, abbreviation S-CSCF) three types, that wherein take the main responsibility is S-CSCF.Operation layer is to be made up of a series of application servers (Application Server is called for short AS), and concrete business service can be provided.Key-course (S-CSCF) calls the business on the AS according to user's professional triggering of CAMEL-Subscription-Information control, realizes business function.

End-to-end equipment in the session is called subscriber equipment (User Equipment, be called for short UE), be responsible for mutual with the user, the UE that has has the mode of multiple access network, comprise packet switch (the Packet Switch by 3GPP, be called for short PS) the territory access network, can also be by circuit switching (Circuit Switch, abbreviation CS) territory access network etc.

Be linked in the IMS network in the CS territory, mobile switching centre's (Mobile Switch Center is called for short MSC) or Mobile Switching Center Server (MSC Server) are linked into the IMS network as the control network element of signaling plane.If the CS network configuration (the enhanced Mobile Switch Center of enhancing mobile switching centre, be called for short eMSC), provide SIP (Session Initial Protocol by eMSC, initial session protocol) interface comes and the IMS network interaction, and then IMS network and CS network can realize by eMSC alternately.Can be referred to as eMSC with MSC or the MSC Server of IMS network interaction in this article.

For the UE with plurality of access modes, if this UE constantly can only use a kind of access way, then it is carrying out talk business under the access way of 2/3G network, because talk business is provided by the CS territory in the 2/3G network, when UE moves to other places and needs its access way of using of change be LTE (Long Term Evolution, Long Term Evolution) network or HSPA (high speed packet access, high-speed packet inserts) during network insertion, the talk business that UE and network can provide certain mode that UE is being carried out is not interrupted, because talk business is provided by the PS territory in these networks, we are referred to as singly to treat the continuity of terminal traffic from CS to PS such ability, be called for short reverse single standby service continuity (CS to PS Single Radio Voice Call Continuity-CS to PS SRVCC), corresponding with it, then be referred to as singly to treat the terminal traffic continuity if UE moves to the 2/3G network from LTE network or HSPA network, abbreviate single standby service continuity as.

In order to realize CS to PS SRVCC business, in the IMS network, introduce ATCF (Access Transfer Control Function, insert transmission control function), be the signaling anchor point of session in the IMS network, can reduce session switches to the PS territory from the CS territory the time interval, improve the user and experience.ATCF is by the IMS network allocation when UE is registered to the IMS network by the PS territory.When the control network element registration of UE by the CS territory time the IMS network, the IMS network can be notified to the information of ATCF the control network element in CS territory.The control network element in CS territory is initiated the heavy registration process of IMS, in the path with the subsequent session that ATCF joined the CS territory.

In specific implementation, UE may set up the back in the session in CS territory by the IMS registration process in PS territory and take place, be that ATCF just distributes after the session in CS territory is set up, this session is not because be anchored on ATCF so, can lead to the failure so carry out CS to PS SRVCC business, the session switching of namely carrying out from the CS territory to the PS territory can be failed.A kind of possibility is also arranged, and UE is after the session in CS territory is set up, and ATCF changes, and namely up-to-date ATCF is not in the signaling paths of former session, and the switching of the session from the CS territory to the PS territory also can be failed so.

Fig. 1 is the flow chart of existing C S to PS SRVCC, and among the figure, eMSC is the network element for the CS territory of UE1 service, and P-CSCF, ATCF, S-CSCF and AS (Application Server, application server) are the network element in the IMS network of UE1 service.UE1 has been registered to the CS territory, and eMSC replaces the user to carry out the IMS registration.But this moment, UE1 did not carry out the IMS registration by the PS territory, did not also distribute ATCF.As shown in the figure, UE1 has set up a session in the CS territory, and carries out Signalling exchange by the AS in eMSC and the IMS network, because do not have ATCF this moment, so the signaling of this session is anchored on the AS of IMS network.The signalling interactive process of AS in eMSC and the IMS network may be through network elements such as I-CSCF or S-CSCF, and this is prior art, and is easy in order to describe, and does not draw at this.Detailed process is as follows:

Step 101:UE1 sends session and sets up request to the base station, session is set up in request.Send set up request such as terminal;

Step 102: the base station sends to eMSC with the session request of setting up;

Step 103:eMSC sends session to S-CSCF/AS and sets up request, sends the SIP INVITE such as eMSC to S-CSCF/AS,

For for simplicity, not writing out alternately between S-CSCF and the AS only represented with S-CSCF/AS herein.Wherein AS also may be SCC AS, only represents with AS herein.

Step 104:S-CSCF/AS sends to UE2 with the session request of setting up;

Step 105:UE2 returns session and sets up response, the request of accepting session;

In actual implementation procedure, may carry out repeatedly Signalling exchange between UE1 and the UE2 and set up process to finish session, for easy, do not give unnecessary details at this.

Step 106:S-CSCF/AS sends session to eMSC and sets up response;

Step 107～step 108:eMSC sets up response with session and sends to the base station, and the base station is set up response with session and sent to UE1;

So far, UE1 sets up in the session in CS territory and finishes.Do not comprise ATCF in the signaling paths of this session.

Step 109:UE1 initiates the IMS registration process by the PS territory.P-CSCF selects one to be the ATCF of this UE1 service in this registration process, and the information of ATCF brings S-CSCF/AS in message in the IMS registration process;

This ATCF is used for the session handoff procedure from CS to the PS territory, and is mutual with the switching anchor point of media gateway as the signaling anchor point of UE1 in the IMS network, reduces handover delay, improves the user and experiences.

After step 110:eMSC receives the message of the information of carrying ATCF that S-CSCF/AS sends, replace UE1 to initiate IMS registration or the heavy registration process in CS territory, in this process, ATCF is joined in the registered paths;

The information of this ATCF is such as the address that is ATCF, or the sign of ATCF etc.

After the IMS in CS territory registers or heavily registration is finished, when eMSC sets up new session, ATCF can be joined in the signaling paths of new session, this ATCF is as the signaling anchor point of this new session at the IMS network.When this new session need switch to the PS territory, ATCF can carry out alternately with ATGW (Access Transfer Gateway inserts transport gateway), and ATCF and ATGW switch to IMS signaling anchor point and the medium anchor point in PS territory respectively as session.

Step 111: the base station determines session is switched to the PS territory from the CS territory according to measurement report;

Step 112: the base station sends the handover request that UE1 is switched to PS from CS to eMSC;

Step 113:eMSC sends handover request to ATCF;

After step 114:ATCF received handover request, the session of setting up before finding did not have grappling in the above, and namely in the signaling paths of session, ATCF can't not carry out the handoff procedure in PS territory to ATCF.ATCF returns the handoff failure response to eMSC;

The another possibility execution mode of step 113～step 114 is that eMSC sends CS to the handover request of PS to AS.After AS receives this handover request because its can't successful execution CS to the handoff procedure of PS, can cause the oversize failure scene that waits of handover delay.AS returns the response message of handoff failure to eMSC.

Step 115:eMSC returns the response message of handoff failure to the base station;

Step 116: continue follow-up operation.

In the prior art, terminal can't successful switch under the situation in PS territory, can select to switch to other CS territory.But the process need of the step 113～step 114 cost regular hour, the overlay area that may cause terminal to shift out network, also lost the opportunity that switches to other CS territories.Finally cause session loss, influence the user and experience.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of improved reverse single standby service continuity implementation method, accelerates the session handoff procedure from the CS territory to the PS territory, the signaling consumption when shortening handoff failure.

In order to address the above problem, the invention provides a kind of improved reverse single standby service continuity implementation method, comprising:

Strengthen mobile switching centre (eMSC) and know that IP Multimedia System (IMS) network is that the circuit commutative field (CS) of described terminal distribution is to the signaling anchor positioning information of packet-switched domain (PS) switching, when described eMSC receive terminal switched to the handover request of PS from CS after, if judge not comprise the IMS network in the signaling paths of described terminal current sessions for the signaling anchor point that the CS of this terminal distribution switches to PS, then stop the described terminal CS of execution to the switching of PS.

Further, if described eMSC judges that not comprising the IMS network in the signaling paths of described terminal current sessions is the CS of this terminal distribution signaling anchor point to the PS switching, comprising:

Described eMSC is according to the information that whether comprises described signaling anchor point in the described terminal current sessions signaling paths recording of information route header field, perhaps, the information that whether comprises described signaling anchor point in the route header field according to described terminal current sessions signaling paths information judges in the signaling paths of described terminal current sessions whether comprise described signaling anchor point.

Further, described eMSC stops execution CS to the switching of PS, and comprising: eMSC returns the switching refuse information.

Further, described eMSC know the IMS network be the CS of terminal distribution to the signaling anchor positioning information that PS switches, comprising:

EMSC knows that by IMS registration process or heavy registration process the IMS network is that the CS of terminal distribution is to the signaling anchor positioning information of PS switching; Perhaps

Initial session protocol (SIP) message that eMSC sends by application server (AS) or service call conversation control function (S-CSCF) knows that the IMS network is that the CS of terminal distribution is to the signaling anchor positioning information of PS switching;

Described signaling anchor positioning information comprises: the address or the sign that insert transmission control function (ATCF) entity.

Another technical problem that the present invention will solve provides a kind of improved reverse single standby service continuity implementation method, avoids the session handoff failure of UE from the CS territory to the PS territory that may occur.

In order to address the above problem, the present invention also provides a kind of improved reverse single standby service continuity implementation method, comprising:

Strengthen after mobile switching centre (eMSC) knows that IP Multimedia System (IMS) network is the signaling anchor positioning information that switches to packet-switched domain (PS) of the circuit commutative field (CS) of described terminal distribution, if judge in the signaling paths of described terminal current sessions and do not comprise described signaling anchor point, then the base station sends message under the described terminal, forbids that it initiates described terminal CS to the switching of PS.

Further, described method also comprises: be the terminal with reverse single standby service continuity capability and signatory reverse single standby service continuity business when described eMSC judges described terminal, and all comprising the IMS network in the signaling paths of current all sessions of this terminal is that the CS of this terminal distribution is to the signaling anchor point of PS switching, then described eMSC base station under this terminal sends message, allows it to initiate the CS of described terminal to the switching of PS.

The technical problem to be solved in the present invention provides a kind of improved reverse single standby service continuity implement device, accelerates the session handoff procedure from the CS territory to the PS territory, the signaling consumption when shortening handoff failure.

In order to address the above problem, the present invention also provides a kind of improved reverse single standby service continuity implement device, is positioned to strengthen mobile switching centre (eMSC), comprises information acquisition module, judge module and processing module, wherein:

Described information acquisition module is used for knowing that IP Multimedia System (IMS) network is that the circuit commutative field (CS) of terminal distribution is to the signaling anchor positioning information of packet-switched domain (PS) switching;

Described judge module, whether comprising the IMS network for the signaling paths of judging described terminal current sessions is that the CS of this terminal distribution is to the signaling anchor point of PS switching;

Described processing module is used for stoping and carrying out described terminal CS to the switching of PS when described judge module judges that the signaling paths of described terminal current sessions does not comprise described signaling anchor point.

Further, described processing module is for the switching that stops the described terminal CS of execution to PS in the following ways:

Described processing module base station under the described terminal sends message, forbids that it initiates described terminal CS to the switching of PS.

Further, described device also comprises receiver module, and it is used for receiving the handover request that terminal is switched to PS from CS;

Described judge module is for after receiving described handover request at described receiver module, judges that whether comprising the IMS network in the signaling paths of described terminal current sessions is the CS of this terminal distribution signaling anchor point to the PS switching;

Described processing module is for the switching that stops the described terminal CS of execution to PS in the following ways: described processing module is returned the switching refuse information.

Further, described judge module is used for also judging that described terminal is the terminal with reverse single standby service continuity capability and signatory reverse single standby service continuity business, and all comprising the IMS network in the signaling paths of current all sessions of this terminal is that the CS of this terminal distribution is to the signaling anchor point of PS switching, then notify described processing module base station under the described terminal to send message, allow it to initiate the CS of described terminal to the switching of PS;

Described processing module also is used for sending message according to the notice of described judge module base station under the described terminal, allows it to initiate the CS of described terminal to the switching of PS.

Further, described judge module is whether to comprise described signaling anchor positioning information for the signaling paths information of judging this terminal current sessions in the following ways:

If described judge module is judged the information that comprises described signaling anchor point in described terminal current sessions signaling paths recording of information route header field or the route header field, then judge in the signaling paths information of described terminal current sessions and comprise described signaling anchor positioning information, if judge the information that does not comprise described signaling anchor point in described record route header field or the route header field, then judge in the signaling paths information of described terminal current sessions not comprise described signaling anchor positioning information.Described signaling anchor positioning information comprises: the address or the sign that insert transmission control function (ATCF) entity.

Further, described information acquisition module is for knowing that in the following ways the IMS network is the signaling anchor positioning information that the CS of terminal distribution switches to PS:

Know that in the IMS of described eMSC registration process or heavy registration process the IMS network is that the CS of terminal distribution is to the signaling anchor positioning information of PS switching; Perhaps

Know that by initial session protocol (SIP) message that application server (AS) or service call conversation control function (S-CSCF) entity send the IMS network is that the CS of terminal distribution is to the signaling anchor positioning information of PS switching.

In the signaling anchor point that the CS that the inventive method and device do not anchor to specific I MS network and provide in user's session switches to PS, eMSC returns error message to the base station in advance, the signaling consumption under the shortening switching failure scene.

Description of drawings

Fig. 1 be in the prior art CS to the flow chart of PS handoff failure;

Fig. 2 is that embodiment of the invention 1CS is to PS switching flow figure;

Fig. 3 is that embodiment of the invention 2CS is to PS switching flow figure;

Fig. 4 is that embodiment of the invention 3CS is to PS switching flow figure;

Fig. 5 is that embodiment of the invention 4CS is to PS switching flow figure;

Fig. 6 is that embodiment of the invention 5CS is to PS switching flow figure;

Fig. 7 is the embodiment of the invention 6 apparatus structure schematic diagrames.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, hereinafter will be elaborated to embodiments of the invention by reference to the accompanying drawings.Need to prove that under the situation of not conflicting, the embodiment among the application and the feature among the embodiment be combination in any mutually.

Embodiment one

As Fig. 2, the figure shows a kind of improved CS to the PS switching flow, reduce Signalling exchange.Specifically, after eMSC receives terminal is switched to the handover request of PS from CS, the signaling anchor positioning information that the CS that is terminal distribution according to signaling paths information and the IMS network of current sessions switches to PS, judge, if being the CS of terminal distribution, the IMS network is not included in the signaling paths information of current sessions to the signaling anchor point that PS switches, eMSC stops the described terminal CS of execution to the switching of PS so, and particularly: eMSC refuses this CS to the PS handover request.

The signaling paths information of session comprises: the parameter in Record-Route (record route) header field; Or the parameter in Route (route) header field.

The background of present embodiment is: UE1 adheres at CS, and registers at the IMS network by the CS territory.But also do not carry out the IMS registration by the PS territory, the signaling anchor point that the CS that does not namely also have the IMS network to distribute for this UE1 switches to PS.As shown in Figure 2, present embodiment comprises the steps:

Step 201a～208a and step 201b～208b are two kinds of different scenes, may carry out wherein any in the specific implementation.

Step 201a:UE1 sends session and sets up request to the base station, session is set up in request, such as sending the setup request;

Step 202a: the base station sends to eMSC with the session request of setting up;

Step 203a:eMSC sends session to S-CSCF/AS and sets up request, sends the SIP INVITE such as eMSC to S-CSCF/AS;

Step 204a:S-CSCF/AS sends to UE2 with the session request of setting up;

Step 205a:UE2 returns session and sets up response, the request of accepting session;

Step 206a:S-CSCF/AS sends session to eMSC and sets up response;

Step 207a～step 208a:eMSC sets up response with session and sends to the base station, and the base station is set up response with session and sent to UE1;

Step 201b:UE2 initiation session is set up request, and session is set up in request;

Step 202b:S-CSCF/AS sends to eMSC with the session request of setting up, such as sending SIP INVITE (invitation) message;

Step 203b:eMSC sends session and sets up request to the base station, such as sending set up message;

Step 204b: the base station sends to UE1 with the session request of setting up;

Step 205b:UE1 returns session and sets up response, the request of accepting session;

Step 206b: the base station sends session to eMSC and sets up response;

Step 207b～step 208b:eMSC sets up response with session and sends to S-CSCF/AS, and S-CSCF/AS sets up response with session and sends to UE2;

Step 209:UE1 initiates IMS registration process (or the heavy registration process of IMS) in the PS territory, P-CSCF selects one to be the ATCF of this UE1 service in this registration process, and the information of ATCF brings S-CSCF/AS by message in the IMS registration process;

Step 210:IMS network (S-CSCF or AS) switches the CS that distributes for UE1 in the IMS network to PS signaling anchor point notice eMSC;

In the present embodiment, IMS network notice eMSC, ATCF are that the CS that distributes for UE1 is to the signaling anchor point of PS switching.Specifically send message to eMSC such as, AS or S-CSCF, carry the signaling anchor positioning information.This message is such as being SIP MESSAGE (message) message, or SIPNOTIFY (notice) message.The mode of carrying of signaling anchor positioning information is such as being that adding an explanation of field ATCF who carries ATCF address or sign in message is anchor point, perhaps such as being to carry feature-tag (feature tag) in message, wherein comprises address or the sign of ATCF.

Step 211:eMSC replaces UE1 to initiate IMS registration or the heavy registration process in CS territory, in this process ATCF is joined in the registered paths;

The IMS in CS territory registration or after heavily registration is finished when eMSC sets up the new session of this UE1, can join ATCF in the signaling paths of new session, and this ATCF is as the signaling anchor point of this new session at the IMS network.When this new session need switch to the PS territory, ATCF can carry out alternately with ATGW, and ATCF and ATGW switch to IMS signaling anchor point and the medium anchor point in PS territory respectively as session.

Step 212: the base station determines session is switched to the PS territory from the CS territory according to measurement report;

Step 213: the base station sends the handover request that UE1 is switched to PS from CS to eMSC;

Step 214:eMSC receives that the base station sends UE1 is switched to the handover request of PS from CS after, judge ATCF not in the signaling paths of this session, then eMSC does not send handover request to the IMS network, switches to the PS territory but refuse session in advance from the CS territory;

Concrete, eMSC judges the method that whether comprises ATCF in the signaling paths of session, such as being: whether comprise the address of ATCF in the Record-Route header field of eMSC according to session or identify and judge; Perhaps, such as be whether comprise in the Route header field of eMSC according to session ATCF the address or the sign judge.The address is such as the URI (Uniform Resource Identifier, generic resource identifier) that is ATCF, or the URI of the sign correspondence of ATCF.The ATCF sign for example can be PSI (the Public Service Identity of ATCF, public service identity), or the STN-SR (Session Transfer Number for SRVCC, the successional session forwarding number of single standby service) that distributes for ATCF etc.

Step 215:eMSC sends to the base station and switches refuse information, such as sending HANDOVER REQUIRED REJECT (handover request refusal) message, the reason of indication refusal in Cause (reason) field;

Step 216: continue follow-up operation.

In the present embodiment, eMSC sends before the handover request to the IMS network, judges earlier, determines not send handover request to the IMS network according to the result who judges, thereby has saved signaling consumption, has improved user's experience.

Embodiment two

As Fig. 3, the figure shows another kind of improved CS to the PS switching flow, reduce Signalling exchange.Specifically, after eMSC receives terminal is switched to the handover request of PS from CS, the signaling anchor positioning information that the CS that is terminal distribution according to signaling paths information and the IMS network of current all sessions switches to PS, judge, if being the CS of terminal distribution, the IMS network is not included in the signaling paths of current arbitrary session to the signaling anchor point that PS switches, eMSC stops the described terminal CS of execution to the switching of PS so, and particularly: eMSC refuses this CS to the PS handover request.

The background of present embodiment is: UE1 adheres at CS, and registers at the IMS network by the CS territory.But also do not carry out the IMS registration by the PS territory, namely also not having the IMS network is that the CS of UE1 distribution is to the signaling anchor point of PS switching.As shown in Figure 3, present embodiment comprises the steps:

Set up session 1 between step 301～step 308:UE1 and the UE2, concrete steps are with the step 201a among the embodiment one～step 208a;

Need to prove that present embodiment is that to exhale with opening of UE1 be that example illustrates, in actual the enforcement, also may be the process of exhaling eventually.In the present embodiment, in the signaling paths of session, all do not comprise ATCF.

Step 309～step 311: with the step 209～step 211 among the embodiment one, ATCF is added in the registered paths, will be as the signaling anchor point when UE1 switches to the IMS network in PS territory;

Step 312:UE1 sends session 2 and sets up request to the base station, session 2 is set up in request, such as sending set up request;

Step 313: the base station sends to eMSC with session 2 requests of setting up;

Step 314:eMSC sends session 2 to ATCF and sets up request, sends the SIP INVITE such as eMSC to ATCF;

Step 315:ATCF is the signaling anchor point that CS that UE1 distributes switches to PS as the IMS network, send session 2 to S-CSCF/AS and set up request, such as ATCF to S-CSCF/AS transmission SIP INVITE;

Step 316:S-CSCF/AS sends to UE2 with the session request of setting up;

Step 317:UE2 returns session 2 and sets up response, the request of accepting session;

In actual implementation procedure, may carry out repeatedly Signalling exchange between UE1 and the UE2 and set up process to finish session 2, for easy, do not give unnecessary details at this.

Step 318～step 319:S-CSCF/AS sets up response with session 2 and returns to eMSC through ATCF;

Step 320～step 321:eMSC sets up response with session 2 and returns to UE1 through the base station;

So far, UE1 sets up in the session 2 in CS territory and finishes, and comprises ATCF in the signaling paths of this session 2.

Step 322: the base station determines UE1 is switched to the PS territory from the CS territory according to measurement report;

Step 323: the base station sends to eMSC UE1 is switched to the handover request of PS from CS, such as sending HANDOVER REQUIRED (handover request) message;

Step 324:eMSC receives CS after the handover request of PS, does not comprise ATCF in the signaling paths in the session 1 of judgement UE1, and then eMSC does not send handover request to the IMS network, switches to the PS territory but refuse session in advance from the CS territory;

Step 325:eMSC sends and switches refuse information, such as sending HANDOVER REQUIRED REJECT message, the reason of indication refusal in the Cause field;

Step 326: continue follow-up operation.

Embodiment three

As Fig. 4, the figure shows another kind of improved CS to the PS switching flow, reduce Signalling exchange.Specifically, after eMSC receives terminal is switched to the handover request of PS from CS, the signaling anchor positioning information that switches to PS according to the CS that in the signaling paths information of current all sessions and the IMS network is terminal distribution, judge, if being the CS of terminal distribution, the IMS network is not included in the signaling paths information of current sessions to the signaling anchor point that PS switches, eMSC stops the described terminal CS of execution to the switching of PS so, and particularly: eMSC refuses this CS to the PS handover request.The difference of present embodiment and embodiment 1 is that setting up of present embodiment comprised an ATCF in the session signaling.

The background of present embodiment is: UE1 adheres at PS, and registers at the IMS network by the PS territory, the signaling anchor point of selecting ATCF1 to switch to PS as CS.UE1 also adheres at CS, and registers at the IMS network by the CS territory, and ATCF1 is included in the registered paths.As shown in Figure 4, present embodiment comprises the steps:

Step 401～step 402:UE1 initiation session is set up request, with the step 201a among the embodiment one～step 202a;

Step 403:eMSC sends session to ATCF1 and sets up request message;

Step 404:ATCF1 sets up request message with session and issues S-CSCF/AS;

Step 405:S-CSCF/AS sends to UE2 with the session request of setting up;

Step 406～step 410:UE2 returns session and sets up response, the request of accepting session;

So far, UE1 sets up in the session in CS territory and finishes.Comprise in the IMS network CS that distributes for UE1 in the signaling paths of this session to the signaling anchor point ATCF1 of PS switching.

Need to prove that present embodiment is that to exhale with opening of UE1 be that example illustrates, in actual the enforcement, also may be the process of exhaling eventually.Be in the signaling paths of session, to have comprised ATCF1 with the difference of embodiment 1.

Step 411: because reasons such as network initiation or registration timeout are initiated IMS and gone registration process, initiate IMS such as P-CSCF at registration timeout to go registration;

Step 412:IMS network switches the CS that distributes for UE1 in the IMS network to PS signaling anchor point notice eMSC;

In this embodiment, IMS network notice eMSC ATCF1 no longer is that the CS of UE1 distribution is to the signaling anchor point of PS switching.Specifically send message to eMSC such as, AS or S-CSCF, carry the signaling anchor positioning information.This message is such as being SIP MESSAGE (message) message, or SIPNOTIFY (notice) message.The mode of carrying of signaling anchor positioning information is such as being that adding an explanation of field ATCF1 in message no longer is anchor point; Perhaps such as being not carry ATCF1 in message, expression ATCF1 has not been anchor point.

Step 413:eMSC initiates heavy registration process, and ATCF1 is not in registered paths;

This step 413 may take place also may not take place in reality is implemented.

Step 414:UE1 initiates the IMS registration process in the PS territory, P-CSCF selects one to be the ATCF2 of this UE1 service in this registration process, and this ATCF2 is as the up-to-date signaling anchor point of this UE1 in the IMS network, and the information of ATCF2 brings S-CSCF/AS in message;

Step 415:IMS network (S-CSCF or AS) switches the CS that distributes for UE1 in the IMS network to PS signaling anchor point notice eMSC;

In this embodiment, IMS network notice eMSC, ATCF2 are that the up-to-date CS that distributes for UE1 is to the signaling anchor point of PS switching.Specifically send message to eMSC such as, AS or S-CSCF, carry the signaling anchor positioning information.This message is such as being SIP MESSAGE (message) message, or SIP NOTIFY (notice) message.The mode of carrying of signaling anchor positioning information is such as being to add address or sign that a field is carried ATCF2 in message; Perhaps such as being address or the sign of carrying ATCF2 in the feature-tag the inside.

Step 416:eMSC replaces UE1 to initiate IMS registration or the heavy registration process in CS territory, in this process ATCF2 is joined in the registered paths;

After the IMS in CS territory registers or heavily registration is finished, when eMSC sets up new session, ATCF2 can be joined in the signaling paths of new session, this ATCF2 is as the signaling anchor point of this new session at the IMS network.When this new session need switch to the PS territory, ATCF2 can carry out alternately with ATGW2, and ATCF2 and ATGW2 switch to IMS signaling anchor point and the medium anchor point in PS territory respectively as session.

Step 417: the base station determines session is switched to the PS territory from the CS territory according to measurement report;

Step 418: the base station sends the handover request that UE1 is switched to PS from CS to eMSC;

Step 419:eMSC receives CS after the handover request of PS, judges ATCF2 not in the signaling paths of this session, and then eMSC does not send handover request to the IMS network, switches to the PS territory but refuse session in advance from the CS territory.

Concrete, eMSC judges the method that whether comprises ATCF2 in the signaling paths of session, such as being: whether comprise the address of ATCF2 in the Record-Route header field of eMSC according to session or identify and judge; Perhaps, such as be whether comprise in the Route header field of eMSC according to session ATCF2 the address or the sign judge.The address is such as the URI (Uniform Resource Identifier, generic resource identifier) that is ATCF2, or the URI of the sign correspondence of ATCF2.The ATCF2 sign for example can be PSI (the Public Service Identity of ATCF2, public service identity), or the STN-SR (Session Transfer Number for SRVCC, the successional session forwarding number of single standby service) that distributes for ATCF2 etc.

Step 420:eMSC sends and switches refuse information, such as sending HANDOVER REQUIRED REJECT message, the reason of indication refusal in the Cause field;

Step 421: continue follow-up operation.

UE1 among above-described embodiment 1-3 is for supporting the terminal of CS to PS SRVCC professional ability and signatory CS to PS SRVCC business, because terminal only in this way just can be carried out CS to the switching of PS.

Embodiment four

As Fig. 5, the figure shows another kind of improved CS to the PS switching flow, reduce Signalling exchange.Specifically, eMSC judges whether the terminal current sessions can be implemented to the switching in PS territory, namely whether comprises above-mentioned signaling anchor point in the signaling paths of terminal current sessions after knowing that the IMS network is the signaling anchor positioning information that switches to PS of the CS of terminal distribution; If can not realize, eMSC stops execution terminal CS to the switching of PS, particularly so: the eMSC informing base station, forbid that its initiation CS is to the PS handoff procedure.

The judgement current sessions can realize that the condition of the switching from the CS territory to the PS territory is: comprising the IMS network the signaling paths of this terminal current sessions is that the CS of this terminal distribution is to the signaling anchor point of PS switching.Preferably, can also judge whether described terminal is the terminal of supporting CS to PS SRVCC professional ability and signatory CS to PS SRVCC business this moment.

The background of present embodiment is: UE1 adheres at CS, and registers at the IMS network by the CS territory.But also do not carry out the IMS registration by the PS territory, namely also do not have the CS that distributes for UE1 in the IMS network to the signaling anchor point of PS switching.As shown in Figure 5, present embodiment comprises the steps:

Step 501～step 508: with the step 201a among the embodiment one～step 208a, perhaps with the step 201b among the embodiment one～step 208b.UE1 sets up in the session in CS territory and finishes.Do not comprise ATCF in the signaling paths of this session;

Step 509:UE1 initiates the IMS registration process in the PS territory, P-CSCF selects one to be the ATCF of UE1 service in this registration process, and the information of ATCF brings S-CSCF/AS in message in the IMS registration process;

Step 510:IMS network (AS or S-CSCF) is that the CS that UE1 distributes notifies eMSC to the signaling anchor point that PS switches with the IMS network;

In the present embodiment, IMS network notice eMSC, ATCF are that the CS that distributes for UE1 is to the signaling anchor point of PS switching.Specifically send message to eMSC such as, AS or S-CSCF, carry the signaling anchor positioning information.This message is such as being SIP MESSAGE (message) message, or SIP NOTIFY (notice) message.The mode of carrying of signaling anchor positioning information is such as being that adding an explanation of field ATCF who carries ATCF address or sign in message is anchor point, perhaps such as being to carry feature-tag in message, wherein comprises address or the sign of ATCF.

Step 511:eMSC replaces UE1 to initiate IMS registration or the heavy registration process in CS territory, in this process ATCF is joined in the registered paths;

The IMS in CS territory registration or after heavily registration is finished when eMSC is UE1 when setting up new session, can join ATCF in the signaling paths of new session, and this ATCF is as the signaling anchor point of this new session at the IMS network.When this new session need switch to the PS territory, ATCF can carry out alternately with ATGW, and ATCF and ATGW switch to IMS signaling anchor point and the medium anchor point in PS territory respectively as session.

Above-mentioned steps 511 may take place also may not take place in reality is implemented.

Do not comprise up-to-date ATCF in the signaling paths of step 512:eMSC judgement existing session;

Step 513:eMSC informing base station does not allow to initiate CS and switches to the session of PS.Such as sending CLASSMARK UPDATE (the class mark upgrades) message, the indication base station does not allow to initiate CS to PS SRVCC business;

Step 514: continue follow-up business.

Preferably, after this terminal current sessions finished, eMSC rejudged whether allow to initiate CS to PS SRVCC business, if can initiate, eMSC sends notice to the base station so, and the ban that sends before removing namely allows the base station to initiate CS to PS SRVCC business.The foundation that eMSC rejudges comprises: the IMS network has been terminal distribution ATCF, and the path of all sessions of this terminal all comprises this ATCF, and this terminal is for supporting the terminal of CS to PS SRVCC professional ability and signatory CS to PS SRVCC business.

Embodiment five

As Fig. 6, the figure shows another kind of improved CS to the PS switching flow, reduce Signalling exchange.Specifically, eMSC know the IMS network be the CS of terminal distribution to the signaling anchor positioning information that PS switches, judge whether the terminal current sessions can be implemented to the switching in PS territory; If can not realize, eMSC stops execution terminal CS to the switching of PS, particularly so: the eMSC informing base station, forbid initiating CS to the PS handoff procedure.

Judge that current sessions can realize that the method for the switching from the CS territory to the PS territory is: terminal has CS to PS SRVCC professional ability and signatory CS to PS SRVCC business, and comprises the IMS network in the signaling paths of this terminal current sessions and be the CS of this terminal distribution signaling anchor point to the PS switching.

The background of present embodiment is: UE1 adheres at PS, and registers at the IMS network by the PS territory, the signaling anchor point of selecting ATCF1 to switch to PS as CS.UE1 also adheres at CS, and registers at the IMS network by the CS territory, and ATCF1 is included in the registered paths.As shown in Figure 6, present embodiment comprises the steps:

Step 601～step 610: with the step 401～step 410 among the embodiment two.UE1 sets up in the session in CS territory and finishes, and comprises the CS that distributes for UE1 in the IMS network in the signaling paths of this session to the signaling anchor point ATCF1 of PS switching;

Present embodiment is that to exhale with opening of UE1 be that example illustrates, need to prove, and in reality is implemented, also may be the process of exhaling eventually.In the present embodiment, in the signaling paths of session, comprise ATCF1.

Step 611～step 616: with the step 411～step 414 among the embodiment two.ATCF2 becomes the signaling anchor point that UE1 switches to the IMS network in PS territory;

Do not comprise up-to-date ATCF2 in the signaling paths of step 617:eMSC judgement existing session;

Step 618:eMSC informing base station does not allow to initiate CS and switches to the session of PS.Such as sending CLASSMARK UPDATE message, indication does not allow to initiate CS to PS SRVCC business;

Step 619: continue follow-up business.

Embodiment six

The present embodiment introduction realizes the device of above-described embodiment method, and this device is positioned at eMSC, as shown in Figure 7, comprises information acquisition module, judge module and processing module, wherein:

Described information acquisition module is used for or knows that IP Multimedia System (IMS) network is the signaling anchor positioning information that the circuit commutative field (CS) of terminal distribution switches to packet-switched domain (PS);

Particularly, this processing module is for stop carrying out the switching of described terminal CS to PS in the following ways: processing module transmission message in base station under the described terminal, forbid that it initiates described terminal CS to the switching of PS.

Preferably, this device also comprises receiver module, and it is used for receiving the handover request that terminal is switched to PS from CS; At this moment, judge module is for after receiving described handover request at described receiver module, judges that whether comprising the IMS network in the signaling paths of described terminal current sessions is the CS of this terminal distribution signaling anchor point to the PS switching; Processing module is for the switching that stops the described terminal CS of execution to PS in the following ways: described processing module is returned the switching refuse information.

When this device comprises receiver module, preferably, this judge module is used for also judging that described terminal is the terminal with reverse single standby service continuity capability and signatory reverse single standby service continuity business, and all comprising the IMS network in the signaling paths of current all sessions of this terminal is that the CS of this terminal distribution is to the signaling anchor point of PS switching, then notify described processing module base station under the described terminal to send message, allow it to initiate the CS of described terminal to the switching of PS; This processing module also is used for sending message according to the notice of described judge module base station under the described terminal, allows it to initiate the CS of described terminal to the switching of PS.

Particularly, this information acquisition module is for knowing that in the following ways the IMS network is the signaling anchor positioning information that the CS of terminal distribution switches to PS:

Particularly, this judge module is whether to comprise described signaling anchor positioning information for the signaling paths information of judging this terminal current sessions in the following ways:

If judge module is judged the information that comprises described signaling anchor point in described terminal current sessions signaling paths recording of information route header field or the route header field, then judge in the signaling paths information of described terminal current sessions and comprise described signaling anchor positioning information, if judge the information that does not comprise described signaling anchor point in described record route header field or the route header field, then judge in the signaling paths information of described terminal current sessions not comprise described signaling anchor positioning information.Described signaling anchor positioning information comprises: the address or the sign that insert transmission control function (ATCF) entity.

One of ordinary skill in the art will appreciate that all or part of step in the said method can instruct related hardware to finish by program, described program can be stored in the computer-readable recording medium, as read-only memory, disk or CD etc.Alternatively, all or part of step of above-described embodiment also can use one or more integrated circuits to realize.Correspondingly, each the module/unit in above-described embodiment can adopt the form of hardware to realize, also can adopt the form of software function module to realize.The present invention is not restricted to the combination of the hardware and software of any particular form.

Certainly; the present invention also can have other various embodiments; under the situation that does not deviate from spirit of the present invention and essence thereof; those of ordinary skill in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection range of the appended claim of the present invention.

Claims

1. improved reverse single standby service continuity implementation method comprises:

2. the method for claim 1 is characterized in that:

If described eMSC judges that not comprising the IMS network in the signaling paths of described terminal current sessions is the CS of this terminal distribution signaling anchor point to the PS switching, comprising:

3. method as claimed in claim 1 or 2 is characterized in that:

Described eMSC stops execution CS to the switching of PS, comprising:

EMSC returns the switching refuse information.

4. method as claimed in claim 1 or 2 is characterized in that:

Described eMSC know the IMS network be the CS of terminal distribution to the signaling anchor positioning information that PS switches, comprising:

5. improved reverse single standby service continuity implementation method comprises:

6. method as claimed in claim 5 is characterized in that:

7. as claim 5 or 6 described methods, it is characterized in that:

8. as claim 5 or 6 described methods, it is characterized in that:

Described method also comprises:

Be the terminal with reverse single standby service continuity capability and signatory reverse single standby service continuity business when described eMSC judges described terminal, and all comprising the IMS network in the signaling paths of current all sessions of this terminal is that the CS of this terminal distribution is to the signaling anchor point of PS switching, then described eMSC base station under this terminal sends message, allows it to initiate the CS of described terminal to the switching of PS.

9. an improved reverse single standby service continuity implement device is positioned at enhancing mobile switching centre (eMSC), comprises information acquisition module, judge module and processing module, wherein:

10. device as claimed in claim 9 is characterized in that:

Described processing module is for the switching that stops the described terminal CS of execution to PS in the following ways:

11. device as claimed in claim 9 is characterized in that:

Described device also comprises receiver module, and it is used for receiving the handover request that terminal is switched to PS from CS;

12. device as claimed in claim 11 is characterized in that:

Described judge module is used for also judging that described terminal is the terminal with reverse single standby service continuity capability and signatory reverse single standby service continuity business, and all comprising the IMS network in the signaling paths of current all sessions of this terminal is that the CS of this terminal distribution is to the signaling anchor point of PS switching, then notify described processing module base station under the described terminal to send message, allow it to initiate the CS of described terminal to the switching of PS;

13. as claim 9 or 10 or 11 or 12 described devices, it is characterized in that:

Described judge module is whether to comprise described signaling anchor positioning information for the signaling paths information of judging this terminal current sessions in the following ways:

If described judge module is judged the information that comprises described signaling anchor point in described terminal current sessions signaling paths recording of information route header field or the route header field, then judge in the signaling paths information of described terminal current sessions and comprise described signaling anchor positioning information, if judge the information that does not comprise described signaling anchor point in described record route header field or the route header field, then judge in the signaling paths information of described terminal current sessions not comprise described signaling anchor positioning information; Described signaling anchor positioning information comprises: the address or the sign that insert transmission control function (ATCF) entity.

14. as claim 9 or 10 or 11 or 12 described devices, it is characterized in that:

Described information acquisition module is for knowing that in the following ways the IMS network is the signaling anchor positioning information that the CS of terminal distribution switches to PS: