CN1889756B

CN1889756B - Method for double-mode terminal switching between block field and circuit field

Info

Publication number: CN1889756B
Application number: CN200510036066A
Authority: CN
Inventors: 徐杰; 刘文宇; 尤昉
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2005-07-16
Filing date: 2005-07-16
Publication date: 2010-05-12
Anticipated expiration: 2025-07-16
Also published as: CN1889756A

Abstract

A method for switching two-mode terminal between packet domain and circuit domain includes issuing new call at in circuit domain, judging whether new call is switch or not and routing new call to MGW as well as switching opposite end to MGW then releasing original call if it is when two-mode terminal is switched from packet domain to circuit domain; issuing logon in packet domain by two-mode terminal, using IWGW as B2BUA to connect through two-mode terminal and MGCF after logon is detected and connecting MGCF to apposite end when two-mode terminal is switched from circuit domain to packet domain.

Description

The method that dual-mode terminal switches between packet domain and circuit domain

Technical field

The present invention relates to the handoff technique of mobile communication system, particularly the handoff technique of double-mode terminal cross-domain.

Background technology

In recent years, the communication technology has obtained fast development.(2ndGeneration is to transmit the digital communication system of voice-and-data 2G) to second generation mobile communication system.It also can provide low-rate data service and Short Message Service except that voice communications services is provided.The 2G exemplary systems has the global system for mobile communications (Global System for mobile Communication is called for short " GSM ") of employing time division multiple access (Time Division Multiple Access is called for short " TDMA ") mode etc.

Meanwhile, having carried out at present the commercial 2.5G mobile communication technology of using is from the march toward connecting technology of 3G of 2G.Because though 3G can combine voice communication and multimedia communication, its possible value-added service will comprise image, music, web page browsing, video conference and some other information service, but, 3G is a quite great engineering, the aspect that is involved is many and complicated, and the 3G that march toward from present 2G can not once just be connected.Therefore, 2.5G between 2G and 3G has appearred.2.5G exemplary systems has code division multiple access CDMA20001X (Code Division Multiple Access 20001X is called for short " CDMA20001X ").

We can say that the network coverage at present is exactly the circuit network of 2G or 2.5G the most widely.

In addition, broadband wireless communication technique also obtains fast development in recent years, offer convenience for people's live and work day by day.Typical broadband wireless network has WLAN (wireless local area network) (Wireless Local AreaNetwork is called for short " WLAN ") and HRPD (high rate packet data) (High Rate Packet Data is called for short " HRPD "), is also referred to as CDMA2000EVDO.

Briefly introduce CDMA2000EVDO below.

" DO is Data Only " represents that this technology only supports data and do not support that voice service, main target are to improve the message transmission rate of wave point.CDMA2000EVDO has aloft adopted new modulation technique and has increased methods such as data rate control, optimizing scheduling and time division multiplexing on the interface, makes that the message transmission rate on the air interface has had large increase.Compare with CDMA2000 1x, CDMA2000 EVDO has two big advantages: the peak rate height; Capacity is big, and supported user is many.CDMA2000 EVDO can be widely used in video telephone, streaming media service and the data broadcast service.

At present, operator is in order to provide better business to part high request user, promptly wideer bandwidth, higher access speed, can be at the part hot zones, wireless broadband network of stack on above-mentioned 2G and 2.5G network, and, generally all provide various colourful multimedia services in these broadband services behind by internet protocol multimedia subsystem (IPMultimedia Subsystem is called for short " IMS ").

In this case, there be the dual-mode terminal of part such as dual-mode handset.The dual-mode terminal most important function is to select service network, promptly selects access module.Such as the CDMA2000EVDO network that can forward wireless broadband network to from the CDMA20001X network of 2.5G.That is to say, can either insert wireless broadband network, also can carry out the mandarin sound business by the circuit-domain network of the conventional wireless honeycomb such as CDMA20001X or GSM in the place that does not have wireless broadband network at hot zones.

Thus, in application, produced a problem. on the one hand, when the user after hot zones is initiated an audio call by wireless broadband network, when in communication process, having roamed out the coverage of wireless broadband network, need to solve and continue to guarantee to call out continuously, even the user can continue to continue the problem of conversation under conventional cellular network. on the other hand, when the user initiates a voice call under conventional cellular network after, in communication process, roamed into the wireless broadband network coverage, and this user wishes to increase medium type in conversation, as increase video content conversation is changed into multimedia services such as video calling, then need to solve conversation switched to problem on the wireless broadband network.

At this phenomenon, of the prior art a kind of analog circuit domain handover scheme proposed.According to this scheme, with a newly-increased network entity, be mobile management controlled function (the MobilityManagement Control Function among Fig. 1, be called for short " MMCF ") come (the Mobile Switching Center of mobile switching centre of analog circuit domain, be called for short " MSC "), replace IMS to initiate handoff request, make to call out by the switching flow under the traditional circuit domain network to switch to circuit domain to the MSC that switches the purpose circuit domain.

Fig. 1 to Fig. 6 has done further explanation to the process of above-mentioned analog circuit domain handover scheme.Wherein, Fig. 1 illustrates situation about setting up in this programme before calling out; Fig. 2 illustrates the situation after the call setup in this programme; Fig. 3 illustrates situation from MMCF to circuit domain MSC that initiate switching flow in this programme by; Fig. 4 illustrates the calling of newly setting up circuit domain, former call business stream is switched to the situation of circuit domain from the IMS territory; Fig. 5 illustrates the notice terminal and transfers to the situation that circuit domain continues conversation; Fig. 6 illustrates terminal and forwards the situation that circuit domain continues conversation to.

In actual applications, there is following problem in such scheme: can only be applied to cdma network, can't be applied to other wireless cellular networks such as GSM, be of limited application.And need change existing Access Network, circuit-domain network equipment, certainly will increase the cost of operator.

Cause the main cause of this situation to be, the analog circuit domain switching causes such scheme and Access Network that the close-coupled relation is arranged, what use when particularly switching is CDMA signaling (as " TIA-41MAP " signaling among Fig. 5), therefore, if be cdma network, just can't simulate the cdma network signaling.

Summary of the invention

In view of this, the method that provides a kind of dual-mode terminal to switch between packet domain and circuit domain is provided main purpose of the present invention, makes dual-mode terminal to switch between packet domain and circuit domain when conversation, and applicable to various mobile communication technologies.

For achieving the above object, the invention provides a kind of dual-mode terminal and switch to the method for circuit domain from packet domain, first terminal of bimodulus in packet domain with second terminal call, comprise following steps during switching:

A first terminal is initiated new the calling in circuit domain, and this new calling is triggered to the interoperability gateway, and this interoperability gateway judges whether this new calling is switching;

B then should newly call out and be routed to media gateway if switch, and second terminal is switched to the resource port of this media gateway for this new call distribution, and discharged the former calling in the packet domain;

Wherein, described interoperability gateway is circuit domain and packet domain sharing equipment, is used as service control point in circuit domain, is used as application server in packet domain, plays the effect of switching controls in handoff procedure.

Wherein, in the described steps A, described interoperability gateway can judge whether described new calling is switching by following substep:

Described first terminal is notified described interoperability gateway at needs before circuit domain is switched;

Described interoperability gateway responds described notice, returns first identification number to described first terminal;

Described first terminal is initiated new call out as called number in circuit domain with first identification number;

After should newly call out being triggered to described interoperability gateway by circuit domain, this interoperability gateway judges that according to first identification number should newly call out is switching.

In this external described method, in the described steps A, described interoperability gateway judges according to the called number of described new calling whether this new calling is switching;

When the called number of described new calling when being one of following, described interoperability gateway judges that should newly call out be to switch:

The number of first terminal self or the number of second terminal or predefined number.

In this external described method, described step B further comprises following substep:

If described interoperability gateway is judged described new calling and for switching, then should newly be called out and be routed to media gateway and MGCF thereof;

Described new calling is routed to packet domain by described MGCF, and is triggered to described interoperability gateway in packet domain, notifies resource address and the port numbers of the described media gateway of this interoperability gateway for this new call distribution during triggering;

Described interoperability gateway is initiated the resource refresh flow, notifies described second terminal Media Stream to be switched to the resource port of the described new call distribution of described media gateway;

After the Media Stream switching of described second terminal was finished, described interoperability gateway discharged the former calling in the packet domain.

The present invention also provides a kind of dual-mode terminal to switch to the method for packet domain from circuit domain, first terminal of bimodulus in circuit domain with second terminal call, the signatory in advance call-delivery business of the user of first terminal, and comprise following steps:

H first terminal is initiated new calling in circuit domain, and is receiving that ring-back tone or connection back discharge calling newly, utilize the call-delivery business to make second terminal be transferred to MGCF;

I first terminal is initiated registration in packet domain, and described interoperability gateway detects this registration back and connects first terminal and MGCF in packet domain, and connects this MGCF and second terminal by mobile switching centre;

Wherein, described interoperability gateway is circuit domain and packet domain sharing equipment, is used as service control point in circuit domain, is used as application server in packet domain.

Wherein, described step H further comprises following steps:

Described first terminal is initiated new the calling in circuit domain, and wherein called number is the access code of described interoperability gateway;

This new calling signaling sends to described interoperability gateway by the MGCF route from packet domain, and this interoperability gateway indicates this MGCF to put ring-back tone for first terminal;

After first terminal is received ring-back tone from described interoperability gateway, discharge and newly to call out, utilize the call-delivery business to make second terminal be transferred to described MGCF.

In this external described method, described step H further comprises following steps:

Described first terminal is initiated new the calling in circuit domain, and this new calling is triggered to described interoperability gateway;

Described interoperability gateway judges whether into switching, if then will be somebody's turn to do the access code that the new called number of calling out changes this interoperability gateway into according to the new called number of calling out;

In this external described method, when the called number of described new calling when being one of following, described interoperability gateway judges that should newly call out be to switch:

In this external described method, a kind of implementation of described step I further comprises following substep:

Described first terminal is initiated registration in packet domain;

After described interoperability gateway detects this registration, make a call or make a call to first terminal, in packet domain, connect the described MGCF and first terminal by first terminal as back-to-back user agent;

Mobile switching centre in the described MGCF announcing circuit territory is switched to second terminal with this MGCF.

In this external described method, the another kind of implementation of described step I further comprises following substep:

Described first terminal makes a call, and connects the described MGCF and first terminal in packet domain;

In this external said method, described packet domain is the internet protocol multimedia subsystem territory.

By relatively finding, the main distinction of technical scheme of the present invention and prior art is, dual-mode terminal in conversation when packet domain switches to circuit domain, initiate new the calling in circuit domain earlier, judge by IWGW (interoperability gateway) whether this new calling is switching, be routed to a MGW (media gateway) if then should newly call out, the terminal of the opposite end of will conversing again switches to this MGW, discharges former calling at last.

Dual-mode terminal in conversation when circuit domain switches to packet domain, initiate new the calling in circuit domain earlier, and receiving ring-back tone or connecting the back disconnection, utilize signatory in advance CT business that the opposite end of former conversation is transferred to MGCF, after this dual-mode terminal is initiated registration in packet domain, IWGW detects this registration back as back-to-back user agent (Back to Back User Agent, be called for short " B2BUA ") connect dual-mode terminal and MGCF (MGCF), by MGCF notice MSC MGCF is switched to the opposite end of former conversation again.

Difference on this technical scheme has brought comparatively significantly beneficial effect, and promptly dual-mode terminal can freely switch to circuit domain from packet domain, perhaps switches to packet domain from circuit domain.No matter how the user roams, as long as a kind of in two kinds of networks supporting of dual-mode terminal has signal to cover, conversation just can keep.If the user initiates after the voice call under conventional cellular network, as long as in communication process, roamed into the wireless broadband network coverage, just can carry out abundanter business, as changing conversation into video calling etc. by switching to wireless broadband network.

Because the present invention uses the SIP signaling when switching,, can support other wireless cellular networks such as GSM so with respect to using the CDMA signaling to realize the prior art of switching, there is not dependence in the mode of Access Network; And existing Access Network, circuit-domain network equipment are not changed demand, saved the cost of operator greatly.

Description of drawings

Fig. 1 is in the prior art, sets up the system schematic before calling out;

Fig. 2 is in the prior art, the system schematic after the call setup;

Fig. 3 is in the prior art, by the system schematic of MMCF when circuit domain MSC initiates switching flow;

Fig. 4 is in the prior art, newly sets up the calling of circuit domain, with the system schematic of former call business stream when the IMS territory switches to circuit domain;

Fig. 5 is in the prior art, the system schematic when the notice terminal is transferred to circuit domain continuation conversation;

Fig. 6 is in the prior art, the system schematic when terminal forwards circuit domain continuation conversation to;

Fig. 7 is the schematic diagram of miscellaneous equipment annexation in IWGW and circuit domain, the packet domain;

Fig. 8 is according to the principle of the invention, first system mode schematic diagram when the IMS territory switches to the CS territory;

Fig. 9 is according to the principle of the invention, second system mode schematic diagram when the IMS territory switches to the CS territory;

Figure 10 is according to the principle of the invention, the 3rd system mode schematic diagram when the IMS territory switches to the CS territory;

Figure 11 is according to the principle of the invention, four systems view when the IMS territory switches to the CS territory;

Figure 12 is according to the principle of the invention, the 5th system mode schematic diagram when the IMS territory switches to the CS territory;

Figure 13 is according to the principle of the invention, first system mode schematic diagram when the CS territory switches to the IMS territory;

Figure 14 is according to the principle of the invention, second system mode schematic diagram when the CS territory switches to the IMS territory;

Figure 15 is according to the principle of the invention, the 3rd system mode schematic diagram when the CS territory switches to the IMS territory;

Figure 16 is according to the principle of the invention, four systems view when the CS territory switches to the IMS territory;

Figure 17 is according to the principle of the invention, the 5th system mode schematic diagram when the CS territory switches to the IMS territory;

Figure 18 is according to one embodiment of present invention, and terminal switches to the concrete message flow chart of CDMA2000 1X network from the CDMA2000EVDO network when talking state;

Figure 19 is according to another embodiment of the invention, and terminal switches to the concrete message flow chart of CDMA2000EVDO network from the CDMA20001X network when talking state.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, the present invention is described in further detail below in conjunction with accompanying drawing.

Need to prove, having used application number among the present invention is 200510078750.1, denomination of invention is the newly-increased network entity interoperability gateway (Interwork Gateway is called for short " IWGW ") in the patent application of a kind of methods of net interoperability " realize two ".This specification is quoted in full the specification of this patent application.

In traditional circuit, IWGW is the signatory service control point of a dual-mode subscriber (ServiceControl Point is called for short " SCP ") SERVER, and all calling and called that the user carries out in circuit domain all need to be triggered to this entity and go.Therefore this entity can remain on and play the effect of calling out control in the calling signaling path.

In packet domain, IWGW is the signatory application server of a dual-mode subscriber (ApplicationServer is called for short " AS "); All calling and called that the user carries out in the IMS territory all need to be triggered to IWGW, so this entity can remain on and play the effect of calling out control in the calling signaling path, referring to Fig. 7.

The dual-mode terminal that the present invention is proposed is in communication process below, and the principle and the embodiment that switch to the method in CS territory from packet domain (is example with the IMS territory) are explained and illustrated.

The principle of this method at first is described.

When the user need be in communication process when the IMS territory switches to the CS territory, IWGW can carry out following control:

At first, need to initiate to switch when dual-mode terminal detects in communication process, then can select at first to notify this situation of IWGW, referring to Fig. 8. after this, IWGW can be chosen in and return a special identification number to terminal this moment, also can what not return; Then, dual-mode terminal is initiated a new calling at the CS network, called number can be original conversation object number, the number of dual-mode terminal self, default special identification number, special identification number that IWGW returns or the like, this can be referring to Fig. 9. after this, the CS network can be toggled to IWGW with calling, IWGW can know that according to called number this is a switching, therefore controlling call is routed to MGCF/MGW. then, calling is routed to the IMS territory by MGCF, be triggered to IWGW. IWGW this moment again in the IMS territory and can obtain resource address and the port numbers that MGW distributes, referring to Figure 10. after this, IWGW initiates the resource refresh flow, allow an other end of conversation carry out the Media Stream switching, switching to the newly assigned resource port of MGW gets on, referring to Figure 11. etc. terminal and the success of the other end of conversation after the CS territory is connected, IWGW discharges the calling that terminal was set up in the IMS territory originally. this moment, switching was finished, referring to Figure 12.

The dual-mode terminal of having described the present invention's proposition above switches to the principle of the method in CS territory from the IMS territory in communication process.Below with reference to Figure 18, switching to CDMA2000 1X network from CDMA2000 EVDO network with terminal when the talking state is example, further explains according to principle of the present invention, switches to the detailed process in CS territory from the IMS territory.

As shown in figure 18, at first in step 101, dual-mode terminal detects to be needed under the talking state to initiate to switch, and then uses NOTIFY to notify IWGW by S-CSCF.

After this, in step 102, S-CSCF passes through IWGW by NOTIFY.

Then, in step 103, IWGW passes a HO ID back and switches in order to sign in response message " 200OK ".

Then, in step 104, S-CSCF passes to terminal to response message " 200OK ".

Then, in step 105, terminal newly makes a call at the 1X network, and called number extends this as HO ID.

After this, in step 106, MSC at first implies the location registers flow process.

In step 107, HLR returns user's business datum to MSC.

In step 108, MSC is triggered to IWGW according to user's signatory trigger with calling.

In step 109, IWGW learns that according to HO ID this is a switching flow, so control MSC routes calls to the IMS territory.

After this, in step 110, MSC is sent to MGCF with calling.

In step 111, MGCF control MGW distributes new resource, initiates SIP in the IMS territory and calls out to S-CSCF, wherein new resource address and port numbers is packaged in the INVITE.

After this, in step 112, S-CSCF gives IWGW forwards.

In step 113, after IWGW gets access to the resource port of MGW, initiate more new technological process of medium to an other end of conversation, the new resource information of MGW is passed to an other end.

In step 114, an other end of conversation is updated to Media Stream on the new resource port, and its other resources port is transmitted.

After this, in step 115, IWGW sends " BYE " message and discharges the calling of original IMS territory.

In step 116, S-CSCF is discharged into the calling of terminal.

In step 117, IWGW passes to MGCF/MGW to the resource information of the other end of conversation by 180 response messages.

In step 118, MGCF indicates called beginning ring.

In step 119, IWGW indicates call establishment.

In step 120, MGCF initiates terminal in the CS territory new calling is connected with former calling opposite end, thus, has finished the switching from the CDMA2000EVDO network to CDMA2000 1X network.

More than dual-mode terminal that the present invention the is proposed principle and the embodiment that in communication process, switch to the method in CS territory from the IMS territory be explained and illustrated.Next the dual-mode terminal that the present invention the is proposed principle and the embodiment that switch to the method in IMS territory in communication process from the CS territory is explained and illustrated.

Our ratio juris at first is described.

State before switching, user's call-delivery (Call Transfer in advance should contract, be called for short " CT ") business, so that subsequent operation, referring to Figure 13. by terminal automatically detect or by the user decide in its sole discretion need be in communication process when the CS territory switches to the IMS territory, at first initiate a new calling by terminal, called number is the access code of IWGW. call signaling sends to IWGW by the MGCF route from the IMS territory, IWGW indication MGCF is put ring-back tone to terminal, referring to Figure 14. the new certainly called number of calling out also can not be the access code of IWGW, but the number of dual-mode terminal self, the number of conversation opposite end or default number, because new the calling will be triggered to IWGW, so IWGW can make the called number of newly calling out into the access code of IWGW self when finding to be these particular numbers. terminal is heard after ring-back tone or the edge fit, be released in the conversation of circuit domain. the CT business because the user has contracted, then MSC can not interrupt original calling, the other end of original calling and the call proceeding that newly is initiated to the IMS territory can be arrived together, referring to Figure 15. the user initiates registration again to the IMS territory, IWGW detects after the registered events, make a call to terminal, connect the terminal in MGCF and IMS territory, referring to Figure 16. (user also can not initiate registration, but directly make a call to terminal, connect the terminal in MGCF and IMS territory .) terminal is switched to after the calling of MGCF, MGCF notice MSC is switched to an other end of former conversation with it, finished thus from the CS territory to IMS in switching, referring to Figure 17.

Briefly introduce CT business above below.When terminal and the conversation an other Founder when conversing, terminal is initiated a calling to IWGW in addition, when to the IWGW ring or when having connected IWGW, terminal can withdraw from this conversation, MSC can be automatically converses the other side of conversation and the IWGW continuation that continue, the CT business among Here it is the CDMA.This shows that CT can allow the control user keep calling out, and dials and be third party user, connects another user and third party user then.Shown in the following table reaction of system to each calling party action.

Keep the two party call situation in table 1 calling transfer

State: keep two party call	Condition: a side keeps calling out; The control user puts through the opposing party, or control user and third party user is in two square tube speech phases
State: keep two party call		The calling party action	System response
Controlling party is by " stopping (END) " key	Discharge the control user; Connect two sides in addition.Optionally send caution sound.Enter idle condition.	The calling party action	System response
Controlling party is by " stopping (END) " key		For fear of diverting call or removal third party, the controlling party that no third-party call activates is also pressed " sending (SEND) " key by numeral or not according to numeral	Ignore the numeral that any controlling party sends, discharge the third party.Connect the opposing party and controlling party.Optionally send caution sound.Enter the two party call state.

The dual-mode terminal of having described the present invention's proposition above switches to the principle of the method in IMS territory from the CS territory in communication process.Below with reference to Figure 19, switching to CDMA2000 EVDO network from CDMA2000 1X network with terminal under talking state is that example illustrates according to principle of the present invention, switches to the detailed process in IMS territory from the CS territory.

As shown in the figure, at first in step 201, user's decision or terminal oneself detect and need switch to the IMS territory from the CS territory in communication process, then at first initiate a new calling to MSC, and called number is the access code of IWGW.

In step 202, MSC is toggled to IWGW by " ORREQ " message with calling.

In step 203, IWGW normally returns, and can not carry out control operation.

In step 204, MSC routes the call to MGCF according to called number, prepares to be routed to the IMS territory.

In step 205, MGCF control MGW is distributed the resource end points, initiates the IMS territory then and calls out to S-CSCF.

In step 206, S-CSCF is toggled to IWGW with calling.

In step 207, IWGW preserves the resource end points of MGW, returns 180 responses to MGCF then, and indication is put ring-back tone to called terminal ringing to caller.

In step 208, S-CSCF is transmitted to MGCF with 180.

In step 209, MGCF returns ACM to MSC and indicates to caller and put ring-back tone.

In step 210, terminal is heard after the ring-back tone, disconnects ongoing calling; MSC should maintain former calling, just continue to wait for the new call through in ring simultaneously.

In step 211, terminal is initiated registration again to the IMS territory.

In step 212, S-CSCF notifies IWGW with registration message.

In step 213, IWGW responds registration message.In step 214, S-CSCF responds registration message.

In step 215, the IMS that IWGW newly is initiated to terminal calls out, and the resource port information of MGW is informed terminal.

In step 216, S-CSCF with call proceeding to terminal.

In step 217, this calls out terminal response, and with the resource port information of going up local terminal.

In step 218, S-CSCF is transmitted to IWGW with response.

In step 219, IWGW returns call to MGCF, simultaneously with going up the resource port information of terminal in the IMS territory.

In step 220, MGCF connects terminal and CS territory, and returns the ANM indicating call to the CS territory and connect; MSC can connect an other end of former calling and calling newly after receiving this message.Finished switching thus from CDMA2000 1X network to the CDMA2000EVDO network.

Can clearly be seen that from top embodiment the present invention realizes switching by the SIP signaling,, can support other wireless cellular networks such as GSM so there is not dependence in the mode of Access Network; And existing Access Network, circuit-domain network equipment are not changed demand.

Though by with reference to some preferred embodiment of the present invention, the present invention is illustrated and describes, those of ordinary skill in the art should be understood that and can do various changes to it in the form and details, and without departing from the spirit and scope of the present invention.

Claims

1. a dual-mode terminal switches to the method for circuit domain from packet domain, first terminal of bimodulus in packet domain with second terminal call, it is characterized in that, comprise following steps during switching:

2. dual-mode terminal according to claim 1 switches to the method for circuit domain from packet domain, it is characterized in that in the described steps A, described interoperability gateway can judge whether described new calling is switching by following substep:

3. dual-mode terminal according to claim 1 switches to the method for circuit domain from packet domain, it is characterized in that, in the described steps A, described interoperability gateway judges according to the called number of described new calling whether this new calling is switching;

4. switch to the method for circuit domain according to each described dual-mode terminal in the claim 1 to 3 from packet domain, it is characterized in that described step B further comprises following substep:

5. switch to the method for circuit domain according to each described dual-mode terminal in the claim 1 to 3 from packet domain, it is characterized in that described packet domain is the internet protocol multimedia subsystem territory.

6. a dual-mode terminal switches to the method for packet domain from circuit domain, first terminal of bimodulus in circuit domain with second terminal call, it is characterized in that the signatory in advance call-delivery business of the user of first terminal, and comprise following steps:

I first terminal is initiated registration in packet domain, and the interoperability gateway detects this registration back and connects first terminal and MGCF in packet domain, and connects this MGCF and second terminal by mobile switching centre;

7. dual-mode terminal according to claim 6 switches to the method for packet domain from circuit domain, it is characterized in that described step H further comprises following steps:

8. dual-mode terminal according to claim 6 switches to the method for packet domain from circuit domain, it is characterized in that described step H further comprises following steps:

9. dual-mode terminal according to claim 8 switches to the method for packet domain from circuit domain, it is characterized in that, when the called number of described new calling when being one of following, described interoperability gateway judges that should newly call out be to switch:

10. switch to the method for packet domain according to each described dual-mode terminal in the claim 6 to 9 from circuit domain, it is characterized in that described step I further comprises following substep:

Described first terminal is initiated registration in packet domain;

11. switch to the method for packet domain according to each described dual-mode terminal in the claim 6 to 9 from circuit domain, it is characterized in that described step I further comprises following substep:

12. switch to the method for packet domain according to each described dual-mode terminal in the claim 6 to 9 from circuit domain, it is characterized in that described packet domain is the internet protocol multimedia subsystem territory.