CN101895864A

CN101895864A - Single-mode business continuous implementation method and single-mode business continuity system

Info

Publication number: CN101895864A
Application number: CN2009102521996A
Authority: CN
Inventors: 谢振华; 郝振武; 陶全军
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2009-05-22
Filing date: 2009-12-15
Publication date: 2010-11-24
Anticipated expiration: 2029-12-15
Also published as: CN101895864B

Abstract

The invention relates to a single-mode business continuous implementation method, which comprises the following steps: leading a UE to establish an IMS session anchored to a signaling anchor point with a remote user through a PS network, and transmitting media data of the IMS session through a first media path and a second media path; leading an eMSC to send a call request for switching the IMS session to the signaling anchor point after receiving a switch request which is sent by the PS network and used for switching the IMS session to access through a CS network; leading the signaling anchor point to send a mapping request to an AGW after receiving the call request so as to instruct the AGW to connect a third media path which is newly built for the IMS session between the eMSC and the AGW with the second media path and send a call response to the eMSC; and leading the eMSC to connect the third media path with a CS media path which is newly built for the IMS session between the UE and the eMSC after receiving the call response so as to lead the UE to continue the conversation with the remote user through the CS media path, the third media path and the second media path.

Description

A kind of single radio voice call continuity implementation method and single radio voice call continuity system

Technical field

The present invention relates to the communications field, relate in particular to a kind of single radio voice call continuity implementation method and single radio voice call continuity system.

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 one 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.

Triggering and controlled function professional in the key-course are to be finished by CSCF (Call SessionControl Function is called for short CSCF).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 type, that wherein take the main responsibility is S-CSCF, and I-CSCF is optional network element.

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, and AS can be an independent entity, also may reside among the S-CSCF.

Key-course (S-CSCF) calls the business on the AS according to user's professional triggering of CAMEL-Subscription-Information control, realizes business function.AS and S-CSCF can be referred to as service equipment (Server Equipment is called for short SE).

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

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.

For UE with plurality of access modes, if this UE constantly can only use a kind of access way, under a kind of access way, carrying out a certain business, such as conversation, then move to other zones and when need changing the access way of its use as UE, the business that UE and network can provide certain mode that UE is being carried out is not interrupted, we are referred to as the single-mode terminal business continuance such ability, be called for short single radio voice call continuity (Single Radio Voice Call Continuity is called for short SRVCC).

Fig. 1 is the single radio voice call continuity schematic diagram, describe single-mode terminal UE-1 and IMS terminal UE-2 and set up the signaling paths and the media path of session, and behind the generation single radio voice call continuity, the signaling paths of UE-1 and UE-2 and media path, be simplicity of illustration and description, S-CSCF and business continuance AS (SC AS) are drawn as an entity, use Session Initiation Protocol communication between the two based on the IMS standard.

Single radio voice call continuity has been set up session between UE-1 and UE-2 before taking place, and its signaling paths is described below:

Signaling paths between A102:UE-1 and the P-CSCF, the Session Initiation Protocol by IMS communicates with one another, and for SC AS, this is access end (Access leg) path;

Signaling paths between A104:P-CSCF and the SC AS/S-CSCF, the Session Initiation Protocol by IMS communicates with one another, and for SC AS, this also belongs to access end path (Access leg);

Signaling paths between R101:SC AS/S-CSCF and the UE-2, the Session Initiation Protocol by IMS communicates with one another, and for SC AS, this is remote subscriber path (Remote leg);

After single radio voice call continuity took place, variation had all taken place in signaling paths between UE-1 and UE-2 and media path, and wherein the variation of signaling paths is described below:

Signaling paths between A112:UE-1 and the eMSC, the signaling protocol by the CS territory communicates with one another, and for SC AS, this is access end (Access leg) path;

Signaling paths between A114:eMSC and the SC AS/S-CSCF, the Session Initiation Protocol by IMS communicates with one another, and for SC AS, this also belongs to access end (Access leg) path;

Signaling paths between R101:SC AS/S-CSCF and the UE-2, the Session Initiation Protocol by IMS communicates with one another, and for SC AS, this is remote subscriber (Remote leg) path, and after single radio voice call continuity took place, this remote subscriber path did not change.

Fig. 2 is existing single radio voice call continuity Organization Chart, has described each relevant portion of network or the network element that participate in realizing single radio voice call continuity, and interface between them or annexation, is described below:

Related network elements is described:

UE: subscriber terminal equipment with single radio voice call continuity ability;

CS network: the network that the traditional C business is provided for the user;

PS network: the network that the PS business is provided for the user;

EMSC: handle the handoff request that the PS network sends, shift between the territory of execution session, transfer operation between CS handover operation and territory is associated etc.;

IMS network: the network that the IMS business is provided for the user.

Relevant interface is described:

The internetwork air interface of S202:UE and CS (being called for short CS eats dishes without rice or wine) realizes UE and the internetwork information interaction of CS, as the Um Interface of standard;

The internetwork air interface of S204:UE and PS (being called for short PS eats dishes without rice or wine) realizes UE and the internetwork information interaction of PS, as the Uu interface of standard;

Interface between S206:CS network and eMSC (can be called the CS signaling interface), according to the difference of the concrete network element that connects and difference, interface between eMSC and base station sub-system is the Iu-CS interface of standard, interface between eMSC and other mobile switching centres is the interoffice signaling interface of standard, i.e. E interface and Nc interface;

Signaling interface between S208:PS network and eMSC (can be called hand off signaling interface between the territory) supports that to provide to switch between the territory this interface is the Sv interface of standard;

Signaling interface between S210:PS network and internet, as the SGi interface of standard, this interface can provide IP Data-carrying for the information interaction between UE and internet, because the IMS network is based on internet, therefore can calculate a kind of special internet;

The internetwork signaling paths of S212:eMSC and IMS, can be the I2 interface of the internetwork Session Initiation Protocol based on IMS of the eMSC of standard and IMS, also can be to be connected to form by the standard Nc interface between eMSC and media gateway and media gateway and the internetwork standard Mg of IMS; If the latter, media gateway can become the message translation on the Nc interface sip message of IMS or opposite; Nc interface can be based on Session Initiation Protocol (Nc-SIP), also can be based on ISUP (ISDN User Protocol, integrated services digital network User Agreement) agreement (Nc-ISUP).Though Nc-SIP is the same with the I2 interface based on Session Initiation Protocol, but agreement has only been stipulated the form of message, the content of message uses the I2 interface to show that then eMSC supports the application that IMS is relevant by using decision, uses the Nc-SIP interface to show that then eMSC supports the application that traditional C is relevant.

Fig. 3 is existing single radio voice call continuity implementation method flow chart, described and set up the IMS session between UE-1 and UE-2, thereby set up the IMS media path, this IMS media path is made up of the media path between UE-1 and the internetwork media path of PS and PS network and UE-2, after single radio voice call continuity takes place in UE-1, UE-1 and network realize allowing UE-1 use the CS territory to set up media path, and keep the continuous process of former session, comprise the steps:

Step 301, UE-1 are by sending measurement report with the internetwork S204 interface of PS to the PS network that is its service, to report the cell signal strength metrical information;

Step 302, the PS network (former PS network) of serving for UE-1 are more suitable for the service into UE-1 according near the CS network the signal strength information judgement of each sub-district in the measurement report, so decision execution handover operation;

Respective network elements in step 303, the former PS network, such as Mobility Management Entity (MobileManagement Entity, be called for short MME), by the S208 interface between PS network and eMSC, send handoff request to eMSC, such as sending Handover request (handoff request) message, carry the number information of UE-1 and the number information that is used for the request of identification service continuity that the PS network passes through the SC AS of home subscriber server (HomeSubscriber Server is called for short HSS) acquisition in this message;

The CS switching flow of step 304, eMSC operative norm is to prepare the media link resource of target CS network;

Step 305, finish the CS switching flow after, eMSC sends switching response message by the S208 interface to the PS network, such as sending Handover response (handoff response) message;

After step 306, PS network are received switching response message, send switching command message by the S204 interface to UE-1, notice UE-1 switches to the CS territory;

After step 307, UE-1 receive switching command message, access way is adjusted into by the CS territory inserts;

So far set up the CS media path between UE-1 and eMSC, this media path is made up of the CS media path between UE-1 and the internetwork CS media path of CS and CS network and eMSC.

Following steps occur in after the step 303, do not have ordinal relation with step 304～307.

After step 308, eMSC receive the handoff request message of PS network transmission, send call request to SC AS;

Above-mentioned call request sends by the signaling paths (can be called the signaling paths that interconnects) of S212, can be INVITE (invitation) message of SIP therefore, also can be IAM (initial address message) message of ISUP; Carry the number information of UE-1 and the number information of SC AS in this call request, wherein the number information of SC AS is as called party information, and the number information of UE-1 is as caller information.

Step 309, SC AS finally can receive the SIP INVITE of being transmitted the IMS that comes by CSCF, and this is a business continuance request to SC AS according to the called party information decidable, search out with this according to caller information and call out related ongoing calling;

Step 310, SC AS are on the ongoing calling signaling path of association, by the update request of CSCF to UE-2 transmission IMS, such as sending UPDATE (renewal) or reINVITE (heavily inviting) message;

After step 311, UE-2 receive update request, respond the agreement updating message of IMS, such as sending " 200OK " message;

After step 312, SC AS receive the agreement updating message of being transmitted by CSCF, signaling paths by S212 sends call answering message to eMSC, such as sending " 200OK " message, what eMSC finally received may be " 200OK " message of SIP, also may be ANM (response message) message of ISUP;

So far, set up new media path between eMSC and UE-2, eMSC will this newly-built media path and the CS media path connect, UE-1 can be continued and UE-2 converses.

As from the foregoing, do not carry out the grappling of media path owing to be arranged on the SC AS of home network, therefore adopt existing single radio voice call continuity implementation method, in step 310～311, need carry out remote subscriber and upgrade operation, and the delivery lag of IMS signaling that carry out to upgrade operation is long, need wait for still after this will cause the CS medium to be set up that new media path of long period could set up, thereby make the dropped calls overlong time.

Summary of the invention

Technical problem to be solved by this invention is, overcomes the deficiencies in the prior art, the single radio voice call continuity implementation method and the single radio voice call continuity system that provide a kind of medium that need not remote subscriber to upgrade.

In order to address the above problem, the invention provides a kind of single radio voice call continuity implementation method, this method comprises:

UE sets up by PS network and remote subscriber and anchors to the IMS session of signaling anchor point, and transmits the media data of described IMS session by first media path and second media path; Described signaling anchor point is: P-CSCF or SC AS; Described first media path is the IMS media path between UE and the AGW, and described second media path is the IMS media path between AGW and the remote subscriber;

After being used for of receiving that the PS network sends switched to handoff request by the CS network insertion with described IMS session, eMSC sent to described signaling anchor point and is used for call request that described IMS session is switched;

After receiving described call request, described signaling anchor point sends the mapping request to AGW, with indication AGW with between eMSC and the AGW for the 3rd newly-built media path of described IMS session links to each other with described second media path, and to eMSC transmission call answering;

After receiving described call answering, eMSC with between described the 3rd media path and UE and the eMSC for the newly-built CS media path of described IMS session links to each other, make UE pass through described CS media path, the 3rd media path and second media path and converse with the remote subscriber continuation.

In addition, in the following way described the 3rd media path is linked to each other with described CS media path with described second media path respectively:

Described signaling anchor point is included in the transport address of the port H that carries in the described call request in the mapping request and sends to AGW;

After receiving described mapping request, AGW sets up the incidence relation of port H and described second media path, and the transport address of port J is included in the mapping response sends to described signaling anchor point;

After receiving described mapping response, described signaling anchor point is included in the transport address of port J in the described call answering and sends to eMSC;

After receiving described call answering, eMSC sets up the incidence relation of described CS media path and described port J;

Described port H is used among the eMSC receive the media data that remote subscriber sends, and it is sent to the 3rd media path port of UE by described CS media path; Described port J is used among the AGW receive the media data that UE sends, and it is sent to the 3rd media path port of remote subscriber by described second media path.

The line number L1 that described signaling anchor point is held the eMSC that carries in the described call request is included in the mapping request and sends to AGW;

After receiving described mapping request, AGW distributed lines L2 will link to each other with described second media path with described the 3rd media path of line number L1 and L2 sign, and line number L2 is included in mapping will send to described signaling anchor point in responding;

After receiving described mapping response, described signaling anchor point is included in line number L2 in the described call answering and sends to eMSC;

After receiving described call answering, eMSC will link to each other with described CS media path with described the 3rd media path of L2 sign with line number L1.

The line number L1 that described signaling anchor point is held the eMSC that carries in the described call request is included in the lane assignment request and sends to AGW;

After receiving described lane assignment request, AGW distributed lines L2, and line number L2 is included in the lane assignment response sends to described signaling anchor point;

After receiving the response of described lane assignment, described signaling anchor point is included in line number L1 and/or line number L2 in the mapping request and sends to AGW;

After receiving described mapping request, AGW will link to each other with described second media path with described the 3rd media path of L2 sign with line number L1, and return the mapping response to described signaling anchor point;

In addition, UE sets up described IMS session with remote subscriber in the following way:

UE sends the IMS call request to described signaling anchor point, comprises the transport address of the port B of the media data that is used to receive the remote subscriber transmission among the UE in this request;

After receiving described IMS call request, be used to receive the port F of the media data of remote subscriber transmission among the AGW that described signaling anchor point request AGW distributes with port B is associated, and the transport address of port F is included in the IMS call request sends to remote subscriber;

After receiving the IMS call answering that remote subscriber returns, described signaling anchor point is extracted the transport address that the remote subscriber that wherein comprises is used to receive the port x of the media data that UE sends, and be used to receive the transport address of port D of the media data of UE transmission among the AGW that request AGW distributes with port x is associated, and the transport address of port D is included in the IMS call answering sends to UE.

The present invention also provides a kind of single radio voice call continuity system, comprises PS network, CS network, eMSC, it is characterized in that this system also comprises: AGW and as the P-CSCF or the SC AS of the signaling anchor point of IMS session; When UE sets up the IMS session that anchors to described signaling anchor point by described PS network and remote subscriber, and after transmitting the media data of described IMS session by first media path and second media path:

Described eMSC is used to receive that described PS network sends is used for described IMS session is switched to handoff request by described CS network insertion, and sends to described signaling anchor point after receiving described handoff request and be used for call request that described IMS session is switched;

After receiving described call request, described signaling anchor point sends the mapping request to described AGW, with indicate described AGW with between eMSC and the AGW for the 3rd newly-built media path of described IMS session links to each other with described second media path, and to described eMSC transmission call answering;

After receiving described call answering, described eMSC with between described the 3rd media path and UE and the eMSC for the newly-built CS media path of described IMS session links to each other, make UE pass through described CS media path, the 3rd media path and second media path and converse with the remote subscriber continuation;

Wherein, described first media path is the IMS media path between described UE and the described AGW, and described second media path is the IMS media path between described AGW and the described remote subscriber.

Described signaling anchor point is included in the transport address of the port H that carries in the described call request in the mapping request and sends to described AGW;

After receiving described mapping request, described AGW sets up the incidence relation of port H and described second media path, and the transport address of port J is included in the mapping response sends to described signaling anchor point;

After receiving described mapping response, described signaling anchor point is included in the transport address of port J and sends to described eMSC in the described call answering;

After receiving described call answering, described eMSC sets up the incidence relation of described CS media path and described port J;

Described port H is used among the described eMSC receive the media data that described remote subscriber sends, and it is sent to the 3rd media path port of described UE by described CS media path; Described port J is used among the described AGW receive the media data that described UE sends, and it is sent to the 3rd media path port of described remote subscriber by described second media path.

The line number L1 that described signaling anchor point is held the described eMSC that carries in the described call request is included in the mapping request and sends to described AGW;

After receiving described mapping request, described AGW distributed lines L2 will link to each other with described second media path with described the 3rd media path of line number L1 and L2 sign, and line number L2 is included in mapping will send to described signaling anchor point in responding;

After receiving described mapping response, described signaling anchor point is included in line number L2 and sends to described eMSC in the described call answering;

After receiving described call answering, described eMSC will link to each other with described CS media path with described the 3rd media path of L2 sign with line number L1.

The line number L1 that described signaling anchor point is held the described eMSC that carries in the described call request is included in and sends to described AGW in the lane assignment request;

After receiving described lane assignment request, described AGW distributed lines L2, and line number L2 is included in the lane assignment response sends to described signaling anchor point;

After receiving the response of described lane assignment, described signaling anchor point is included in line number L1 and/or line number L2 in the mapping request and sends to described AGW;

After receiving described mapping request, described AGW will link to each other with described second media path with described the 3rd media path of L2 sign with line number L1, and return the mapping response to described signaling anchor point;

In addition, described UE sets up described IMS session with described remote subscriber in the following way:

Described UE sends the IMS call request to described signaling anchor point, comprises the transport address of the port B of the media data that is used to receive described remote subscriber transmission among the described UE in this request;

After receiving described IMS call request, be used to receive the port F of the media data of described remote subscriber transmission among the described AGW that the described AGW of described signaling anchor point request distributes with port B is associated, and the transport address of port F is included in sends to described remote subscriber in the IMS call request;

After receiving the IMS call answering that described remote subscriber returns, described signaling anchor point is extracted the transport address that the remote subscriber that wherein comprises is used to receive the port x of the media data that described UE sends, and ask described AGW to distribute to be used among the described AGW that is associated with port x to receive the transport address of port D of the media data of UE transmission, and the transport address of port D is included in sends to described UE in the IMS call answering.

In sum, the present invention is by the signaling and the medium of grappling IMS session, and upgrades the near-end of media path when single radio voice call continuity takes place, and keeps the distant end media path, the operation of having avoided the medium to remote subscriber to upgrade has reduced break period of conversation.

Description of drawings

Fig. 1 is the single radio voice call continuity schematic diagram;

Fig. 2 is existing single radio voice call continuity Organization Chart;

Fig. 3 is existing single radio voice call continuity implementation method flow chart;

Fig. 4 is the single radio voice call continuity first framework embodiment schematic diagram of the present invention;

Fig. 5 is single radio voice call continuity first method flow diagram that the present invention is based on the first framework embodiment;

Fig. 6 is single radio voice call continuity second method flow diagram that the present invention is based on the first framework embodiment;

Fig. 7 is the single radio voice call continuity second framework embodiment schematic diagram of the present invention;

Fig. 8 is the single radio voice call continuity third party method flow chart that the present invention is based on the second framework embodiment;

Fig. 9 is the cubic method flow chart of single radio voice call continuity that the present invention is based on the second framework embodiment.

Embodiment

Core concept of the present invention is that P-CSCF or SC AS are set up the IMS session as signaling anchor point, AGW as media anchor point; After single radio voice call continuity takes place, to carry out by correlating sessions signaling terminating no longer being continued to transmit alternately with AGW as the P-CSCF or the SC AS of signaling anchor point, and upgrade the near-end in former conversation media path, maintenance distant end media path is constant.

Describe the present invention below in conjunction with drawings and Examples.

The first framework embodiment

Fig. 4 is the single radio voice call continuity first framework embodiment schematic diagram of the present invention, and Fig. 4 has described each relevant portion of network or the network element of realizing single radio voice call continuity, and interface between them or annexation; Specifically describe as follows:

Related network elements is described:

PS network: the network that the PS business is provided for the user;

IMS network: the network that the IMS business is provided for the user.

Comprise network elements such as P-CSCF in the IMS network; In addition, in the present embodiment, in the IMS network, increased network element AGW (Access GateWay, visit gateway) newly.

In the present embodiment, in P-CSCF, increased IMS control point (IMS Control Point abbreviates ICP as) function newly, with the signaling anchor point of P-CSCF as the IMS session, signaling paths to the IMS session carries out grappling, and control AGW Resources allocation, mapping or related media path.

AGW:, be used to realize the forwarding of media data as the media anchor point of IMS session.

Relevant interface is described:

S402～S408: identical with the S202～S208 among Fig. 2;

Because P-CSCF is the IMS network element, so UE and the not demonstration and description of the internetwork signaling interface of IMS, it is the IMS standard interface.

CS signaling interface between S414:eMSC and P-CSCF, be used for transmitting the message of eMSC and P-CSCF (ICP) link setup process, such as CS territory standard N c interface, this interface can be based on the Nc-SIP interface of SIP, also can be based on the Nc-ISUP interface of ISUP;

Signaling interface between S416:P-CSCF (ICP) and AGW makes P-CSCF (ICP) control AGW Resources allocation, mapping or related media path.

First pass embodiment

Fig. 5 is single radio voice call continuity first method flow diagram that the present invention is based on the first framework embodiment; Fig. 5 has described the process of setting up the IMS session between UE-1 and UE-2, and after IMS session foundation is finished, single radio voice call continuity takes place in UE-1, how UE-1 and network realize allowing UE-1 use the media path of CS territory foundation, and keep the continuous process of former session, wherein use the Nc-SIP interface between eMSC and P-CSCF, this method comprises the steps:

Step 501～502, UE-1 initiate the IMS call request, and such as sending INVITE, this call request is carried on the IP carrying of PS network foundation, therefore can pass through the PS network; Carry UE-1 in this call request and be used for the transport addresses information of receiving media data, be expressed as B; This call request is routed to P-CSCF;

Step 503, P-CSCF distribute address resource to the AGW request, such as sending allocation request message, carry transport addresses information B in this message;

Step 504, AGW distribute port resource C and F, and set up the incidence relation of port F and transport address B, make the media data of receiving from port F all need to be forwarded to transport address B; Wherein, port F is used to receive the media data that remote subscriber sends, and port C is used to transmit the media data that port F receives; AGW agrees to distribute to P-CSCF then, such as sending assignment response message, the transport addresses information of carrying port F in this message; In order to simplify description, the transport addresses information of port F correspondence still is expressed as F, and transport addresses information comprises IP address and port numbers;

If the calling that the UE-1 desire is set up comprises more than a kind of medium, then B comprises the transport addresses information that a plurality of UE-1 are used for receiving media data, step 503 can be a message, carry the transport addresses information that a plurality of UE-1 are used for receiving media data in this message, also can be a plurality of message, carry the transport addresses information that a UE-1 is used for receiving media data in each message respectively; Correspondingly, step 504 also can be a message of carrying a plurality of port transmission address informations, or a plurality of message of carrying a port transmission address information respectively, and the specific implementation method does not influence essence of the present invention.

Step 505, P-CSCF preserve transport address F, and use the transport address B of the IMS call request in the transport address F replacement step 502, transmit the IMS call request to remote subscriber then;

After step 506, remote subscriber receive the IMS call request, send the IMS call answering,, carry the transport addresses information that remote subscriber is used for receiving media data in this message, be expressed as X such as sending " 200OK " message;

After step 507, P-CSCF receive the IMS call answering, distribute address resource,, carry transport addresses information X in this message such as sending allocation request message to the AGW request;

Step 508, AGW distribute port resource D and E, and set up the incidence relation of port D and transport address X, and the media data that makes port D receive all needs to be transmitted to transport address X; Wherein, port D is used to receive the media data that UE-1 sends, and port E is used to transmit the media data that port D receives; AGW agrees to distribute to P-CSCF then, and such as sending assignment response message, the transport addresses information of carrying port D in the message is described for simplifying, and the transport addresses information of port D correspondence still is expressed as D;

If X comprises the transport addresses information that a plurality of remote subscribers are used for receiving media data, step 507 can be a message, carry the transport addresses information of a plurality of receiving media datas in this message, also can be a plurality of message, carry the transport addresses information of a receiving media data in each message respectively; Correspondingly, step 508 also can be a message of carrying a plurality of port transmission address informations, or a plurality of message of carrying a port transmission address information respectively, and the specific implementation method does not influence essence of the present invention.

Step 509～510, P-CSCF preserve transport address D, and the transport address X in the IMS call answering in the use transport address D replacement step 506, transmit the IMS call answering to UE-1 then; This message is without any IMS network element; This message is actual to be by passing to UE-1 on the IP carrying that is carried on the foundation of PS network, therefore can passing through the PS network;

So far, UE-1 and remote subscriber have been set up the IMS media path, comprising the IMS media path 2 (being called for short IMS medium 2) between the IMS media path 1 between UE-1 and AGW (being called for short IMS medium 1) and AGW and remote subscriber.

Step when below taking place to switch between the territory for UE-1 is described.

Step 511, UE-1 send measurement report to the PS network that is its service, to report the cell signal strength metrical information;

Step 512, near the CS network of the signal strength information of each sub-district in the network based measurement report of PS of UE-1 service judging is more suitable for the service into UE-1, so handover operation is carried out in decision;

Respective network elements in step 513, the PS network sends handoff request such as MME to eMSC, such as sending Handover request (handoff request) message, carries the number information of UE-1 in this message;

The CS switching flow of step 514, eMSC operative norm is to prepare the media link resource of target CS network;

Step 515, finish the CS switching flow after, eMSC sends switching response message to the PS network, such as sending Handover response (handoff response) message;

After step 516, PS network are received switching response message, send switching command message to UE-1, notice UE-1 switches to the CS territory;

After step 517, UE-1 receive switching command message, access way is adjusted into by the CS territory inserts;

Following steps occur in after the step 513, do not have ordinal relation with step 514～517.

After step 518, eMSC receive the handoff request message of PS network transmission, send call request to P-CSCF, this request sends by the signaling paths of S414, the S414 interface uses the Nc-SIP interface in the present embodiment, what therefore send is INVITE (invitation) message of SIP, carry the number information of UE-1 and the number information of P-CSCF in this message, wherein the number information of P-CSCF is as called party information, and the number information of UE-1 is as caller information; In addition, also carry eMSC in this message and be used to receive the transmission of media data address H that remote subscriber sends;

The call request that step 519, P-CSCF determination step 518 receive is the handoff request of the call request that receives of step 502, therefore asks AGW to carry out map operation, such as sending Maprequest (mapping request) message, carries transport address H in this message; In addition, also carry the transport address F of IMS media path 2 in this message, or the transport address D of IMS media path 1;

In this step, the call request that P-CSCF can come determination step 518 to receive according to the specific P-CSCF number that carries in the call request is a handoff request; Perhaps the all-calls request that eMSC is sent all is judged to be handoff request.

Step 520, AGW find IMS media path 2 according to transport address F or transport address D, and execution map operation, newly-built media path between eMSC and the AGW and IMS media path 2 are carried out relatedly (promptly setting up the incidence relation of port F and transport address H, make the media data of receiving from port F all be forwarded to transport address H), and distribute new near-end media data receiving port J, be used to receive the media data that eMSC sends, describe for simplifying, the transport addresses information of port J correspondence still is expressed as J; After map operation was finished, AGW sent the mapping response message by the S416 interface to P-CSCF, such as sending Map response (mapping response) message, carried the transport address J that AGW is used for receiving media data in this message;

After step 521, P-CSCF receive the mapping response, to the call answering message that eMSC sends Nc-SIP,, carry transport address J in this message such as sending " 200OK " message by the S414 interface;

After eMSC receives call answering message, associate to remote subscriber transmission transmission of media data address G and transport address J being used among the eMSC, make the media data that receives from transport address G be forwarded to transport address J, and transport address G and transport address H and CS media path between UE and the eMSC are carried out related, be respectively applied for from this CS media path and receive media data that UE sends and the media data that sends remote subscriber by this CS media path to UE.

So far, set up new IMS media path between eMSC and AGW, eMSC should newly-built media path carries out relatedly with the CS media path, and AGW should newly-built media path carries out relatedly with IMS media path 2, UE-1 can be continued and UE-2 converses.

Above-mentioned newly-built medium media path comprises: the eMSC side is used for receiving from the CS media path media data of UE, and sends it to the port G of remote subscriber; The eMSC side is used to receive the media data of remote subscriber, and sends to the port H of UE by the CS media path; The AGW side is used for the media data that receiving port G sends, and it is sent to the port J of remote subscriber by port E; The AGW side is used for transmitting to port H the port I of the media data of remote subscriber.

The second flow implementation example

Fig. 6 is single radio voice call continuity second method flow diagram that the present invention is based on the first framework embodiment; Fig. 6 has described the process of setting up the IMS session between UE-1 and UE-2, and after IMS session foundation is finished, single radio voice call continuity takes place in UE-1, how UE-1 and network realize allowing UE-1 use the media path of CS territory foundation, and keep the continuous process of former session, wherein use the Nc-ISUP interface between eMSC and P-CSCF, this method comprises the steps:

Step 601～617, identical with step 501～517;

Following steps occur in after the step 613, do not have ordinal relation with step 614～617.

After step 618, eMSC receive the handoff request message of PS network transmission, send call request to P-CSCF, this request sends by the signaling paths of S414, the S414 interface uses the Nc-ISUP interface in the present embodiment, therefore what send is the IAM message (also can be called the call request of ISUP) of ISUP, carries the line number L1 that eMSC is used to transmit the line resource of CS medium in this message; In addition, also carry the number information of UE-1 and the number information of P-CSCF in this message, wherein the number information of P-CSCF is as called party information, and the number information of UE-1 is as caller information;

The call request that receives in step 619, the P-CSCF determination step 618 is the handoff request of the call request that receives in the step 602, alternatively, P-CSCF request AGW carries out the lane assignment operation, such as sending Line Alloc request (lane assignment request) message, carry the line number L1 of eMSC end in this message, this message transmits by the S416 interface;

After step 620, AGW receive the lane assignment request, divide the line resource that is used in transmission CS medium, its corresponding line number is L2, give P-CSCF by S416 interface transmitting line assignment response then, such as sending Line Alloc response (lane assignment response) message, carry the line number L2 of distribution in this message;

Step 621, P-CSCF request AGW carry out map operation, such as sending Map request (mapping request) message, carry the line number L1 of eMSC end in this message; If carried out step 619～620, the also line number L2 of portability AGW end in this message also carries the transport address F of IMS media path 2 or the transport address D of IMS media path 1 in this message;

Step 622, AGW carry out map operation, to carry out related with media path and IMS media path 2 between the AGW with the eMSC of line number L1 and L2 sign, and pass through the S416 interface to P-CSCF transmission mapping response message, such as sending Map response (mapping responds) message;

If there is not execution in step 619～620, before carrying out above-mentioned map operation, AGW distributes new being used to transmit the line resource of CS media data, and corresponding line number is made as L2;

If there is not execution in step 619～620, carry line number L2 in the above-mentioned mapping response message; If carried out 619～620, can not carry line number L2 in this message.

After step 623, P-CSCF received the mapping response, by the call answering message of S414 interface to eMSC transmission Nc-ISUP, such as sending ANM, the AGW that carries acquisition in this message was used to transmit the line number L2 of CS media data;

After eMSC receives above-mentioned call answering message, carry out related with the media path of line number L1 and L2 sign with CS media path between UE and the eMSC with above-mentioned.

So far set up new CS media path between eMSC and AGW, eMSC will this newly-built media path carries out related with UE with CS media path between eMSC, AGW should newly-built CS media path carries out relatedly with IMS media path 2, UE-1 can be continued and UE-2 converses.

The second framework embodiment

Fig. 7 is the single radio voice call continuity second framework embodiment schematic diagram of the present invention, and Fig. 7 has described each relevant portion of network or the network element of realizing single radio voice call continuity, and interface between them or annexation; Specifically describe as follows:

Related network elements is described:

PS network: the network that the PS business is provided for the user;

IMS network: the network that the IMS business is provided for the user.

Comprise network elements such as CSCF, SC AS in the IMS network; In addition, in the present embodiment, in the IMS network, increased network element AGW (Access GateWay, visit gateway) newly.

SC AS: the business continuance application server functionality that is used to realize the IMS standard; In the present embodiment, new control AGW Resources allocation in SC AS, the function of mapping or related media path;

AGW:, be used to realize the forwarding of IP media data as the media anchor point of IMS session.

Relevant interface is described:

S702～S708: identical with the S202～S208 among Fig. 2;

Because SC AS is the IMS network element, so UE and the not demonstration and description of the internetwork signaling interface of IMS, it is the IMS standard interface.

S714: identical with the S212 among Fig. 2;

Signaling interface between S716:SC AS and AGW makes SC AS control AGW Resources allocation, mapping or related media path;

Signaling interface between the CSCF of S718:SC AS and IMS, this interface are the ISC interface of IMS standard.

The 3rd flow implementation example

Fig. 8 is the single radio voice call continuity third party method flow chart that the present invention is based on the second framework embodiment; Fig. 8 has described the process of setting up the IMS session between UE-1 and UE-2, and after IMS session foundation is finished, single radio voice call continuity takes place in UE-1, how UE-1 and network realize allowing UE-1 use the media path of CS territory foundation, and keep the continuous process of former session, wherein use the I2 interface of IMS standard between eMSC and SC AS; Describe for simplifying, Fig. 8 is drawn in SC AS and CSCF together, and this method comprises the steps:

Step 801～802, UE-1 initiate the IMS call request, and such as sending INVITE, this call request is carried on the IP carrying of PS network foundation, therefore can pass through the PS network; Carry UE-1 in this call request and be used for the transport addresses information of receiving media data, be expressed as B; This call request is routed the AS to SC, and the IMS message transmission between UE and SC AS is by standard procedure each CSCF network element through standard I MS;

Step 803, SC AS distribute address resource to the AGW request, such as sending allocation request message, carry transport addresses information B in this message;

Step 804, AGW distribute port resource C and F, and set up the incidence relation of port F and transport address B, make the media data of receiving from port F all need to be forwarded to transport address B; Wherein, port F is used to receive the media data that remote subscriber sends, and port C is used to transmit the media data that port F receives; AGW agrees to distribute to SC AS then, such as sending assignment response message, the transport addresses information of carrying port F in this message; In order to simplify description, the transport addresses information of port F correspondence still is expressed as F, and transport addresses information comprises IP address and port numbers;

If the calling that the UE-1 desire is set up comprises more than a kind of medium, then B comprises the transport addresses information that a plurality of UE-1 are used for receiving media data, step 803 can be a message, carry the transport addresses information that a plurality of UE-1 are used for receiving media data in this message, also can be a plurality of message, carry the transport addresses information that a UE-1 is used for receiving media data in each message respectively; Correspondingly, step 804 also can be a message of carrying a plurality of port transmission address informations, or a plurality of message of carrying a port transmission address information respectively, and the specific implementation method does not influence essence of the present invention.

Step 805, SC AS preserve transport address F, and use the transport address B of the IMS call request in the transport address F replacement step 802, transmit the IMS call request to remote subscriber then;

After step 806, remote subscriber receive the IMS call request, send the IMS call answering,, carry the transport addresses information that remote subscriber is used for receiving media data in this message, be expressed as X such as sending " 200OK " message;

After step 807, SC AS receive the IMS call answering, distribute address resource,, carry transport addresses information X in this message such as sending allocation request message to the AGW request;

Step 808, AGW distribute port resource D and E, and set up the incidence relation of port D and transport address X, and the media data that makes port D receive all needs to be transmitted to transport address X; Wherein, port D is used to receive the media data that UE-1 sends, and port E is used to transmit the media data that port D receives; AGW agrees to distribute to SC AS then, and such as sending assignment response message, the transport addresses information of carrying port D in the message is described for simplifying, and the transport addresses information of port D correspondence still is expressed as D;

If X comprises the transport addresses information that a plurality of remote subscribers are used for receiving media data, step 807 can be a message, carry the transport addresses information of a plurality of receiving media datas in this message, also can be a plurality of message, carry the transport addresses information of a receiving media data in each message respectively; Correspondingly, step 808 also can be a message of carrying a plurality of port transmission address informations, or a plurality of message of carrying a port transmission address information respectively, and the specific implementation method does not influence essence of the present invention.

Step 809～810, SC AS preserve transport address D, and the transport address X in the IMS call answering in the use transport address D replacement step 806, transmit the IMS call answering to UE-1 then; This message is actual to be by passing to UE-1 on the IP carrying that is carried on the foundation of PS network, therefore can passing through the PS network; IMS message transmission between SC AS and UE is by standard procedure each CSCF network element through standard I MS;

Step 811, UE-1 send measurement report to the PS network that is its service, to report the cell signal strength metrical information;

Step 812, near the CS network of the signal strength information of each sub-district in the network based measurement report of PS of UE-1 service judging is more suitable for the service into UE-1, so handover operation is carried out in decision;

Respective network elements in step 813, the PS network sends handoff request such as MME to eMSC, such as sending Handover request (handoff request) message, carries the number information of UE-1 in this message;

The CS switching flow of step 814, eMSC operative norm is to prepare the media link resource of target CS network;

Step 815, finish the CS switching flow after, eMSC sends switching response message to the PS network, such as sending Handover response (handoff response) message;

After step 816, PS network are received switching response message, send switching command message to UE-1, notice UE-1 switches to the CS territory;

After step 817, UE-1 receive switching command message, access way is adjusted into by the CS territory inserts;

Following steps occur in after the step 813, do not have ordinal relation with step 814～817.

After step 818, eMSC receive the handoff request message of PS network transmission, send call request to SC AS, this request sends by the signaling paths of S714, the S714 interface is the I2 interface of IMS standard in the present embodiment, what therefore send is INVITE (invitation) message of SIP, carry the number information of UE-1 and the number information of SC AS in this message, wherein the number information of SC AS is as called party information, and the number information of UE-1 is as caller information; In addition, also carry eMSC in this message and be used to receive the transmission of media data address H that remote subscriber sends;

The call request that step 819, SC AS determination step 818 receive is the handoff request of the call request that receives of step 802, therefore asks AGW to carry out map operation, such as sending Map request (mapping request) message, carries transport address H in this message; In addition, also carry the transport address F of IMS media path 2 in this message, or the transport address D of IMS media path 1;

Step 820, AGW find IMS media path 2 according to transport address F or transport address D, and execution map operation, newly-built media path between eMSC and the AGW and IMS media path 2 are carried out relatedly (promptly setting up the incidence relation of port F and transport address H, make the media data of receiving from port F all be forwarded to transport address H), and distribute new near-end media data receiving port J, be used to receive the media data that eMSC sends, describe for simplifying, the transport addresses information of port J correspondence still is expressed as J; After map operation was finished, AGW sent the mapping response message by the S716 interface to SC AS, such as sending Map response (mapping response) message, carried the transport address J that AGW is used for receiving media data in this message;

After step 821, SC AS receive the mapping response, to the call answering message that eMSC sends Nc-SIP,, carry transport address J in this message such as sending " 200OK " message by the S714 interface;

So far, set up new media path between eMSC and AGW, eMSC should newly-built media path carries out relatedly with the CS media path, and AGW should newly-built media path carries out relatedly with IMS media path 2, UE-1 can be continued and UE-2 converses.

In addition, in the present embodiment, the interface between eMSC and the SC AS also can be the Nc-SIP interface, promptly carries out the mutual of message by media gateway between eMSC and the SC AS; In this case, the newly-built media path between eMSC and AGW is made up of CS media path between eMSC and media gateway and the IMS media path between media gateway and AGW, and concrete flow process is identical with Fig. 8.

The 4th flow implementation example

Fig. 9 is the cubic method flow chart of single radio voice call continuity that the present invention is based on the second framework embodiment; Fig. 9 has described the process of setting up the IMS session between UE-1 and UE-2, and after IMS session foundation is finished, single radio voice call continuity takes place in UE-1, how UE-1 and network realize allowing UE-1 use the media path of CS territory foundation, and keep the continuous process of former session, wherein use the Nc-ISUP interface between eMSC and SC AS; Describe for simplifying, Fig. 9 is drawn in SC AS and CSCF together; This method comprises the steps:

Step 901～917, identical with step 801～817;

Following steps occur in after the step 913, do not have ordinal relation with step 914～917.

After step 918, eMSC receive the handoff request message of PS network transmission, send call request to SC AS, this request sends by the signaling paths of S714, the S714 interface uses the Nc-ISUP interface in the present embodiment, therefore what send is the IAM message (also can be called the call request of ISUP) of ISUP, carries the line number L1 that eMSC is used to transmit the line resource of CS medium in this message; In addition, also carry the number information of UE-1 and the number information of SC AS in this message, wherein the number information of SC AS is as called party information, and the number information of UE-1 is as caller information;

The call request that receives in step 919, the SC AS determination step 918 is the handoff request of the call request that receives in the step 902, alternatively, SC AS request AGW carries out the lane assignment operation, such as sending Line Alloc request (lane assignment request) message, carry the line number L1 of eMSC end in this message, this message transmits by the S716 interface;

After step 920, AGW receive the lane assignment request, divide the line resource that is used in transmission CS medium, its corresponding line number is L2, give SC AS by S716 interface transmitting line assignment response then, such as sending Line Alloc response (lane assignment response) message, carry the line number L2 of distribution in this message;

Step 921, SC AS request AGW carry out map operation, such as sending Map request (mapping request) message, carry the line number L1 of eMSC end in this message; If carried out step 919～920, the also line number L2 of portability AGW end in this message also carries the transport address F of IMS media path 2 or the transport address D of IMS media path 1 in this message;

Step 922, AGW carry out map operation, to carry out related with media path and IMS media path 2 between the AGW with the eMSC of line number L1 and L2 sign, and pass through the S716 interface to SCAS transmission mapping response message, such as sending Map response (mapping responds) message;

If there is not execution in step 919～920, before carrying out above-mentioned map operation, AGW distributes new being used to transmit the line resource of CS media data, and corresponding line number is made as L2;

If there is not execution in step 919～920, carry line number L2 in the above-mentioned mapping response message; If carried out 919～920, can not carry line number L2 in this message.

After step 923, SC AS received the mapping response, by the call answering message of S714 interface to eMSC transmission Nc-ISUP, such as sending ANM, the AGW that carries acquisition in this message was used to transmit the line number L2 of CS media data;

So far set up new media path between eMSC and AGW, eMSC will this newly-built media path carries out relatedly with UE and CS media path between eMSC, and AGW should newly-built media path carries out relatedly with IMS media path 2, UE-1 can be continued and UE-2 converses.

In the present embodiment, carry out the mutual of message by media gateway between eMSC and the SC AS, the media path between eMSC and AGW is made up of the media path between the media path between eMSC and media gateway and media gateway and AGW.

Claims

1. a single radio voice call continuity implementation method is characterized in that, this method comprises:

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

In the following way described the 3rd media path is linked to each other with described CS media path with described second media path respectively:

3. the method for claim 1 is characterized in that,

4. the method for claim 1 is characterized in that,

5. the method for claim 1 is characterized in that,

UE sets up described IMS session with remote subscriber in the following way:

6. a single radio voice call continuity system comprises PS network, CS network, eMSC, it is characterized in that this system also comprises: AGW and as the P-CSCF or the SC AS of the signaling anchor point of IMS session; When UE sets up the IMS session that anchors to described signaling anchor point by described PS network and remote subscriber, and after transmitting the media data of described IMS session by first media path and second media path:

7. system as claimed in claim 6 is characterized in that,

8. system as claimed in claim 6 is characterized in that,

9. system as claimed in claim 6 is characterized in that,

10. system as claimed in claim 6 is characterized in that,

Described UE sets up described IMS session with described remote subscriber in the following way: