CN1856162A - Domain switching controller, and its method and system - Google Patents

Abstract

A method and system for inter-domain switching and the domain switching controller used. In the system including the first and second domains, a domain switching controller that can be routed to in both domains is set, so as to sign up for inter-domain switching services The dual-mode terminal A in the network designates a domain switching controller; when terminal A initiates a call to other terminals from the first domain, it establishes a signaling connection between the first domain and the domain switching controller, and saves terminal A to the first The call information from the domain to other terminals is associated; when terminal A needs to switch to the second domain, it initiates a call from the second domain, and notifies the domain switching controller to switch with the number of terminal A; the domain switching controller instructs to create the first domain Inter-domain call with the second domain, and establish signaling links and bearer links from terminal A to the second domain, then to the first domain, and then to other terminals; then instruct to release the connection from the first domain to terminal A Signaling link and bearer link. The method of the invention can realize seamless switching of calls between at least two different domains.

Description

Method and system for inter-domain switching and domain switching controller used

technical field

The invention relates to an inter-domain switching method and a device for controlling call seamless switching between two domains in a wireless communication system.

Background technique

In the second generation mobile communication system, there are two domains in the mobile communication system: GSM (Global System for Mobile communications, Global System for Mobile Communications) and GPRS (General Packet Radio Service, General Packet Radio Service). GSM mainly provides voice services and circuit type data services, while GPRS mainly provides high-speed data services. At the stage of Release 99 and Release 4 of the third-generation mobile communication system, the GSM and GPRS domains in the second-generation communication system have evolved into the UMTS CS (Universal Mobile Telecommunications System Circuit Switched) domain and the UMTS PS (Universal Mobile Telecommunications System Circuit Switched) domain respectively. MobileTelecommunications System Packet Switched (General Mobile Communications System Packet Switched) domain, the circuit domain in Release 4 realizes the separation of control and bearer. Both the second generation and the third generation mobile communication systems adopt the coverage mode of the cell. If an ongoing call user moves around the cell, due to the weakening of the cell signal, handover may occur in order to ensure the continuity of the call: the user switches from the first cell with weak signal to the second cell with strong signal , while keeping the call uninterrupted. Since the calls in the two domains are independent of each other, the handover at this time generally occurs within a domain, and the handover is completed by the joint operation of the wireless side and the network side.

ALL IP (all IP) network is the development direction of mobile communication system, so in Release 5, 3GPP (Third Generation Partnership Project, third generation mobile communication partnership project) introduced a new IMS (IP Multimedia Subsystem, IP Multimedia Subsystem) domain, IMS network is an all-IP network, with SIP (Session Initiated Protocol, Session Initiation Protocol) as the core technology, providing users with richer multimedia communication services, including traditional voice services of course .

The IMS defined in Release 5 is an all-IP network framework with UMTS PS domain as access, which realizes the separation of IP control and bearer. The establishment of a call is divided into two parts: signaling link establishment and bearer link establishment. . Release 6 defines the use of WLAN (Wireless Local Area Network, wireless local area network) to access the home IMS to provide VoIP (Voice Over IP, voice service over IP) services, under the coverage of WLAN, it supports most of the existing GSM/UMTS services .

In this way, for a user's voice call, it can be provided through multiple access methods, such as calling through a traditional UMTS CS network, or accessing an IMS through a WLAN (or UMTS PS). Choose a certain access method according to your preference or operator configuration.

The wireless characteristics of different access methods may be different, and wireless coverage may overlap with each other, for example, UMTS CS coverage and WLAN coverage may overlap with each other. In this way, when a voice call accessed from the UMTS CS moves to the edge of the UMTS CS coverage, and then continues to move outward, the call may be interrupted. If the coverage of WLAN is good at this time, the user may wish to switch from UMTS CS coverage to WLAN coverage, while keeping the ongoing call uninterrupted. Since UMTS CS coverage and WLAN coverage are two different domains, the problem of how to switch calls between the two domains arises.

For some real-time services, such as voice calls, users may require that the handover delay is small enough, but for some non-real-time services, such as web page browsing, there is no requirement. Since different domains may belong to different operators, user authentication also needs to be considered during switching. In addition, it is also necessary to consider how to charge during the switching process.

For the above problems, there is no effective solution in the prior art.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for switching between domains in a mobile communication system, which can realize seamless switching of calls between two different domains. The present invention also provides a system for realizing the method and a domain switching controller used therein.

In order to solve the above problems, the present invention provides a method for inter-domain handover in a communication system, comprising the following steps:

(a) In the system that includes at least the first and second domains, set at least one domain switching controller that can be routed to in the two domains, for those who can access the two domains and subscribe to the inter-domain switching service Specify the same domain switching controller for the terminal A of ;

(b) Terminal A initiates a call to other terminals from the first domain, establishes signaling links and bearer links to other terminals through the first domain, and also establishes the first domain and the domain switching during the call establishment process The signaling connection of the controller, the domain switching controller saves the call information from terminal A to the first domain and from the first domain to other terminals, and uses the number of terminal A (this number does not necessarily refer to the mobile phone number, but also refers to terminal A Other unique identifiers in one domain, such as terminal A having different numbers in two domains, the domain switching controller should establish a correspondence between the two numbers) to associate;

(c) When terminal A detects that it needs to switch to the second domain, it initiates a call from the second domain to the domain switching controller, establishes a signaling connection from terminal A to the second domain, and then to the domain switching controller, Notifying the domain switching controller to switch and carry the number of terminal A;

(d) After receiving the notification, the domain switching controller instructs the first or second domain to create an inter-domain call between the first domain and the second domain after checking that the switching is allowed, and transfers the terminal A's number to The call from A to the second domain, the inter-domain call, and the call from the first domain to other terminals are connected, and finally the signaling link and bearer of terminal A to the second domain, then to the first domain, and then to other terminals are established. link, the domain switching controller saves the call information of the three calls and associates them with the number of terminal A;

(e) The domain switching controller instructs to release the signaling link and bearer link from the first domain to terminal A, and maintain the signaling connection with the first domain, and terminal A switches from the first domain to the second domain.

Further, the above-mentioned method can also have the following characteristics: after the step (e1), the following steps are also included:

(f) When terminal A detects that it needs to switch back to the first domain, it notifies the domain switching controller to switch, carrying the number of terminal A;

(g) The domain switching controller instructs to establish a call from the first domain to terminal A, finds and connects an existing call from the first domain to other terminals according to the number of terminal A, establishes terminal A to the first domain, and then Signaling links and bearer links to other terminals;

(h) The domain switching controller instructs to release the signaling link and bearer link from the second domain to the first domain, and from the second domain to terminal A, and terminal A switches from the second domain back to the first domain.

Furthermore, the above method may also have the following features: terminal A may also access the third domain, and subscribe to the inter-domain handover service in this domain and designate it to the domain handover controller, and after the step (e), also Include the following steps:

(f') Terminal A detects the need to subsequently switch to the third domain, initiates a call from the third domain to the domain switching controller, establishes signaling from terminal A to the third domain, and then to the domain switching controller Contact, notify the domain switching controller to switch and carry the number of terminal A;

(g') After receiving the notification, the domain switching controller instructs the first or third domain to create an inter-domain call between the first domain and the third domain when checking that the switching is allowed, and according to the number of terminal A, send The call from terminal A to the third domain, the inter-domain call, and the call from the first domain to other terminals are connected, and finally the signaling link and connection between terminal A to the third domain, then to the first domain, and then to other terminals are established. The bearer link stores the call information of the three calls in the domain switching controller and associates them with the number of terminal A;

(h') The domain switching controller instructs to release the signaling and bearer links from the second domain to the terminal A, and from the second domain to the first domain, and the switching of terminal A from the second domain to the third domain is completed.

Further, the above method may also have the following features: the two domains refer to the UMTS circuit switching domain and the IP Multimedia Subsystem domain, and the domain switching controller is in the UMTS circuit switching domain as a service control point in the IP multimedia subsystem domain as an application server.

Further, the above method may also have the following features: the domain switching controller is also responsible for collecting the charging information of the terminal A in the first domain and the second domain, and associating the charging information of the two domains.

Further, the above method may also have the following features: in the step (f), terminal A initiates a call to the domain switching controller in the first domain, or uses the original second domain to call the domain switching controller The signaling contact of the handover controller notifies the domain handover controller to perform the handover.

Furthermore, the above method may also have the following characteristics: when the domain switching controller connects two calls, for the IP bearer, the bearer information of the two calls is firstly exchanged and negotiated.

Furthermore, the above method may also have the following feature: in the step (c), when the terminal A notifies the domain switching controller to switch, it also carries the bearer information of the terminal A in the second domain.

Further, the above method may also have the following features: in the step (a), when terminal A initiates a call to other terminals from the circuit switched domain, the movement to the domain switching controller is triggered through the first domain The customized application process of the network enhancement logic establishes the dialogue of the application part to realize the signaling connection between each other.

Further, the above method can also have the following characteristics: in the step (a), when terminal A initiates a call to other terminals from the IP multimedia subsystem domain, the call server control function in this domain will determine whether the Carry the number of the domain switching controller in the domain, or whether the user has the attribute of signing the inter-domain switching service to decide whether to route the call to the domain switching controller, the domain switching controller is in the IP multimedia The numbers in the subsystem domain are brought to Terminal A or the Call Server Control Function through the registration process, or configured locally at Terminal A and/and the Call Server Control Function.

Further, the above method can also have the following characteristics: in the step (d), no matter whether terminal A needs to switch from the UMTS circuit switching domain to the IP Multimedia Subsystem domain, or vice versa, the domain switching controller is Instructing the mobile switching center in the circuit switching domain of the UMTS to initiate a cross-domain call, using the number of the domain switching controller in the IP Multimedia Subsystem domain as the destination number.

The domain switching controller in the communication system provided by the present invention includes a switching control module and an information processing module, wherein:

The handover control module further includes: a check unit, used to check the service data of the terminal when the terminal requests handover, and judge whether the handover is allowed; a call creation unit, used to instruct to create a new call on the domain to be handed over to, or Create a new cross-domain call; the call release unit is used to instruct to release the signaling and bearer links from the original domain to the terminal after the handover is completed;

The information processing module is used for saving the related information of calls in the two domains, and associating the call information of the same user in the two domains according to the terminal number.

Further, the above-mentioned domain switching controller can also have the following features: it also includes an information storage module, which is used to store user attribute data and service data, including the attribute of whether the user subscribes to the inter-domain switching service, and is used to judge whether switching is allowed.

Further, the above-mentioned domain switching controller may also have the following features: it also includes a billing module for collecting billing information of the two domains and associating it with corresponding calls.

Further, the above-mentioned domain switching controller may also have the following features: the switching control module further includes a bearer negotiation unit, configured to exchange and negotiate bearer information between two calls.

The communication system capable of inter-domain switching provided by the present invention includes a terminal, and a first domain and a second domain that can communicate with each other, and is characterized in that it also includes at least one domain switching controller, and the domain switching controller is between the first and second domains. In the second domain, they can be routed according to their respective routing methods.

The domain switching controller includes a switching control module and an information processing module. The switching control module is used to judge whether switching is allowed, to instruct to create an intra-domain or inter-domain call on a certain domain, and to instruct to release the information from the original domain to the terminal after switching. Order and bearer links, and exchange and negotiate bearer information between two calls; the information processing module is used to save the call-related information in the two domains, and associate the same user in the two domains according to the set rules call information;

The terminal is a dual-mode terminal, which can access the first domain and the second domain, and can automatically select an access mode. When there is a call or session on a certain domain, the terminal can simultaneously initiate a call or session in another domain. Sign up and chat, or call.

Further, the above-mentioned system may also have the following features: the two domains refer to the Universal Mobile Communications System Circuit Switching domain and the IP Multimedia Subsystem domain, and the domain switching controller is in the Universal Mobile Communications System Circuit Switching domain as a service control point in the IP multimedia subsystem domain as an application server.

It can be known from the above that the present invention proposes a technology for solving switching between different domains, which can realize seamless switching of calls between at least two different domains. Further, after switching from the first domain to the second domain, it is also possible to subsequently switch back to the first domain, or to switch to the third domain subsequently. The technology of the present invention is not limited to solving voice inter-domain switching, but can also be used for other services.

Description of drawings

Fig. 1 shows the embodiment of the present invention that the first terminal accesses from the first domain, initiates a call to the second terminal and establishes a signaling link and a bearer link, wherein the bearer link is represented by a thick solid line, and the signaling link Indicated by a thin solid line.

Fig. 2 is a schematic diagram of the basic principle of switching the first terminal to the second domain according to the embodiment of the present invention.

Fig. 3 is a basic principle diagram of switching back to the first domain by the first terminal according to the embodiment of the present invention.

Fig. 4A, Fig. 4B, Fig. 4C, Fig. 4D are the network diagrams of implementing the switching between the CS domain and the MIS domain in the present invention. Among them, Fig. 4A shows the situation of the UEA calling in the CS domain before the handover; Fig. 4B shows the situation after the UEA is handed over from the CS domain to the IMS domain; Fig. 4C shows the situation of the UEA calling in the IMS domain before the handover; Fig. 4D shows The situation after the UEA is handed over from the IMS domain to the CS domain is shown.

Fig. 5 is a flow chart of the dual-mode terminal calling PSTN in the example of the present invention, and the dual-mode terminal switching from the CS domain to the IMS domain and then switching back to the CS domain.

Fig. 6 is a flow chart of the dual-mode terminal calling PSTN in the example of the present invention, and the dual-mode terminal switching from the IMS domain to the CS domain and then switching back to the IMS domain.

Detailed ways

The schematic diagram of the system in this embodiment is shown in Figure 1, including a first terminal 100, a second terminal 140, a first domain 110, a second domain 120, a called domain 130, and a domain switching controller 150, where the second terminal 140 is located The called domain may be the same as the first and second domains, or may be another domain.

The domain switch controller 150 can be routed to both the first and second domains involved in the switch according to their respective routing modes, and the identifiers and addresses in the two domains may be different. The controller has the following three functional modules related to inter-domain switching:

A handover control module that can simultaneously control calls in two domains involving handover. It further includes a checking unit, which is used to check its service data when the terminal requests switching, and judges whether switching is allowed; a call creation unit, which is used to instruct to create a new call on the domain to be switched to, or to create a new cross-domain call; the call release unit is used to instruct to release the signaling and bearer link from the original domain to the terminal after the handover is completed; the bearer negotiation unit is used to exchange and negotiate bearer information between two calls.

Information processing module: It is used to save the relevant information of the call in the two domains, and associate all the call information of the same user in the two domains according to the set rules, such as the number of the terminal.

Information storage module: used to save the user's attribute data and service data, including the attributes of whether the user subscribes to the inter-domain handover service, and used to judge whether handover is allowed. But this module is optional, and these user data can also be stored on other devices and obtained through access.

The billing module is used for collecting billing information of two domains and associating with corresponding calls.

The terminal implementing switching must use a dual-mode mobile phone, which can access the first domain and the second domain (such as IMS domain and CS domain), and can automatically select an access mode. When there is a call or session on a certain domain , the terminal can simultaneously initiate a registration and a session, or a call, in another domain;

Before the system applies the method of the present invention, the user must sign up for inter-domain switching services in two domains at the same time to have the function of inter-domain switching. Before implementing switching control, the domain switching controller can judge whether to allow or not according to the subscription information. Switch to the destination network. If the two domains are of the same operator, then a certain domain switching controller needs to be designated when signing the contract. If the two domains are of different operators, then an agreement must be reached between the two operators and a common The domain switch controller is used to realize the function of switching between domains. The user's subscription information in the two domains includes the address of the domain switching controller, which may be different in the two domains.

In this embodiment, the method for realizing seamless handover between two different domains includes the following steps:

Step 1: The first terminal 100 initiates a call to the second terminal 140 from the first domain, and establishes a signaling link and a bearer link for the call with the second terminal 140 through the first domain 110. During the call establishment process, At the same time, the signaling connection 112 between the first domain 110 and the domain switching controller 150 is established, and the domain switching controller 150 saves the call information from the first terminal 100 to the first domain 110 and the call information from the first domain 110 to the second terminal 140, and associated with the number of the first terminal 100;

As shown in Figure 1, the signaling link and the bearer link from the first end to the second end are composed of the following three sections: the signaling link 111 and the bearer link 180 from the first terminal to the first domain, and the first domain to The signaling link 113 and the bearer link 181 of the called domain 130, and the signaling link 114 and the bearer link 182 between the called domain and the second terminal. If the called domain and the first domain are the same domain, the bearer links 181 and 182 are combined, and the signaling links 113 and 114 are combined.

Step 2: When the first terminal 100 detects that it needs to switch to the second domain 120, it initiates a call from the second domain 120, the destination number is the number of the domain switching controller 150 in this domain, and establishes a signaling link to the second domain 120 210 and bearer link 250, the second domain 120 establishes a signaling connection 211 with the domain switching controller 150 according to the destination number, and informs the domain switching controller 150 of the number of the first terminal 100, as shown in FIG. 2 ;

Before initiating a call from the second domain, the terminal 100 sometimes needs to initiate a location registration process from the second domain, such as the IMS domain, and initiate a call after the registration process is completed. Some domains can initiate calls without registration, such as UMTS CS domain.

Step 3: When the domain switching controller 150 checks that the first terminal 100 is allowed to switch, it instructs the first domain 100 or the second domain 120 to create an inter-domain call between the first domain and the second domain, and according to the first terminal 100 number, associate the call from the terminal to the second terminal 140 in the first domain 110, the inter-domain call, and the new call of the terminal in the second domain 120, exchange and negotiate the bearer information of adjacent calls when necessary, and finally establish Signaling links (210-213-113-114) and bearer links (250-251-252-182) from the first terminal 100 to the second domain 120, then to the first domain 110, and then to the second terminal 140 ,as shown in picture 2;

In fact, negotiation is only required when IP bears the weight. TDM bearer only needs to connect the circuit time slots of both parties. After negotiation, the bearer 252 to the second terminal in the first domain may be different from the original bearer 181, but the signaling links 113-114 remain unchanged. The way in which the domain switching controller 150 establishes the signaling and bearer between the first domain 110 and the second domain 120 is related to specific domains, and reference may be made to the following two examples.

Step 4: The domain switching controller 150 instructs to release the signaling link 111 and the bearer link 180 of the first terminal 100 in the first domain 110, but the signaling connection 112 from the domain switching controller to the first domain is not released. In this way, the first terminal 100 is switched from the first domain 110 to the second domain 120, and the inter-domain switching controller 150 stores the information from the first terminal 100 to the second domain 120, from the second domain 120 to the first domain 110 and The call information from the first domain 110 to the second terminal 140 is associated with the number of the first terminal 100 .

In the above handover process, for the first terminal, the original bearer to the first domain is disconnected after the new bearer is established, and the bearer is switched to the second domain immediately after disconnection, so it does not feel Business interruption. For the second terminal, if the bearer to the second terminal in the first domain does not need to be re-established, it will not feel that the first terminal is switching, if it needs to be disconnected and re-established according to the negotiation result, then there may be a short time business interruption.

If the first terminal has calls between multiple terminals at the same time, then the domain switching controller must save the call information to all these terminals. When the first terminal switches, the bearer information in the call information to all these terminals may need to be renegotiated.

Please refer to FIG. 3, if the first terminal 100 detects that it needs to switch back to the first domain, it can be realized through the following steps:

Step 5: When the first terminal 100 detects that it needs to switch back from the second domain 120 to the first domain 110, it notifies the domain switching controller 150 to perform the switch, with the user number of the first terminal, and establishes a connection between the first terminal 100 and the first domain. Domain 110 calls;

The first terminal 100 may use the existing signaling links 210 and 211 in the second domain to notify, and after receiving the notification, the domain switch controller 150 will instruct the first domain 110 to establish a call to the first terminal (called procedure ). It is also possible to initiate a call from the first domain 110, use the number of the domain switching controller 150 in this domain as the destination number, establish a call from the first terminal 100 to the first domain 110, and then to the domain switching controller 150 and notify that switching is required .

Step 6. The domain switching controller 150 finds the existing call from the first domain 110 to the second terminal 140 according to the number of the first terminal 100 and associates it with the call from the first terminal 100 to the first domain. Exchange and negotiate bearer information between two calls, and establish signaling links (311-113-114) and bearer links (380-381-182) from the first terminal 100 to the first domain 110 and then to the second terminal 140 ;

Step 7: The domain switch controller 150 instructs to release the inter-domain signaling link 213 and bearer link 251 from the second domain 120 to the first domain 110, and the signaling link 210 and bearer link 251 from the second domain 120 to the first terminal 100. The bearer link 250, in this way, the first terminal 100 is switched back from the second domain 120 to the first domain 110.

If after the first terminal switches from the first domain to the second domain in step four, the first terminal detects that a subsequent switch to the third domain is required, then this is achieved by performing the following steps, provided that: the domain switching controller controlling the first two domains The call of the third domain can be controlled, and the mobile phone of the user can access the third domain, and the inter-domain switching service is signed in this domain and assigned to the domain switching controller.

Step 5', when the first terminal detects that it needs to switch to the third domain, initiate a call from the third domain, the destination number is the number of the domain switching controller in this domain, and establish a signaling link to the third domain and the bearer link, the third domain establishes a signaling connection with the domain switching controller according to the destination number, and informs the domain switching controller of the number of the first terminal;

Step 6', when the domain switching controller checks that the first terminal is allowed to switch from the first domain to the third domain, it instructs the first domain or the third domain to create an inter-domain call between the first domain and the third domain, and according to The number of the first terminal is associated with the call from the terminal to the second terminal in the first domain, the inter-domain call, and the new call of the terminal in the third domain. If necessary, exchange and negotiate the bearer information of adjacent calls, and establish the second terminal. The signaling link and bearer link from a terminal to the third domain, then to the first domain, and then to the second terminal, where the bearer to the second terminal in the first domain may be modified, but the signaling link constant;

Step 7', the domain switching controller instructs to release the signaling and bearer links from the second domain to the first terminal, and from the second domain to the first domain, but the signaling connection between the domain switching controller and the first domain is not released , so that the first terminal switches to the third domain. The above steps are very similar to steps 2, 3 and 4.

In the above process, although the first terminal is the calling party, the above method can also be used to perform inter-domain switching when it is the called party. That is, the switching method of the present invention is the same for the calling party and the called party, and is independent of each other.

The above process will be further described below with two examples. The example involves CS domain and IMS domain in 3GPP. These two domains are independent of each other, and both can provide voice calls. The two domains can communicate with each other.

Figures 4A to 4D are the networking diagrams of two examples, and only some devices are shown. For the specific network structure, please refer to 3GPP TS 23.003. Figure 5 and Figure 6 show two switching processes. The explanation of each network element in the figure is as follows:

UEA: The requirements for UEA are as follows: 1) dual-mode, capable of accessing IMS domain and UMTS CS domain to make calls; 2) able to detect and automatically select an access mode according to operator requirements and user preferences or other standards; 3) When the UE has a UMTS CS call, the UE can simultaneously initiate a registration and a session in the IMS domain; 4) When the UE has an IMS session, the UE can simultaneously initiate or receive a UMTS CS call.

UEA_cs: Functions for handling the CS domain in UEA.

UEA_ims: Functions in UEA that handle IMS domains.

HOAS (Handover Application Server): Handover application server, that is, the domain switching controller above, is mainly responsible for voice call switching between the IMS domain and the UMTS CS domain. The HOAS can be routed in both the CS domain and the IMS domain according to their respective routing modes. And in the UMTS CS domain, HOAS will serve as SCP (Service Control Point, service control point) in Camel (Customized Application for Mobile network EnhancedLogic, customized application of mobile network enhanced logic), and in IMS domain, HOAS will serve as AS ( Application Server, application server).

CSCF (Call Server Control Function): The call server control function in the IMS domain can be divided into P-CSCF (proxy CSCF), I-CSCF (query CSCF) and S-CSCF (serving CSCF).

MGCF (Media Gateway Control Function): The media gateway control function in the IMS domain, which mainly controls the intercommunication to the traditional network.

MSC (Mobile Switching Centre): Mobile Switching Center, responsible for service control in the UMTS CS domain.

PSTN (Public Switched Telephone Network): Public Switched Telephone Network.

IM-MGW: media gateway of the IMS domain;

UEB: The called terminal in the call, in the PSTN network.

Figure 5 is a flow chart of UEA calling PSTN user UEB, UEA switching from CS domain to IMS domain and switching back to CS domain, the steps are as follows:

First, the UEA establishes a call to the PSTN user through the UEA_cs and MSC. The figure shows a radio bearer 450 from UEA_cs to MSC, and a TDM (time-division multiplexing, ie traditional signaling and bearer link) bearer 451 from MSC to PSTN. During the establishment of the call, the MSC triggers the Camel process to the HOAS to establish a CAP (CAMEL Application Part, CAMEL application part) dialogue. The HOAS stores the corresponding relationship between the UEA user number and the CAP dialogue, and stores call information including the dialogue Id of the CAP dialogue, MSC number, etc., as shown in FIG. 4A .

Steps 400-401: UEA finds that the CS call needs to be handed over to the IMS domain according to a certain criterion, so UEA_ims first initiates the IMS domain registration process. After successful registration, UEA_ims sends a call establishment request to the IMS domain, the destination number is the number of the HOAS in this domain, and includes the user number of UEA and the bearer information of UEA. The HOAS number in this domain can be obtained during the registration process, or can be obtained through local configuration of UEA, or other methods. The call request is routed to the destination HOAS through the CSCF in the IMS domain, and the HOAS saves the bearer information of the UEA after receiving it, and uses the user number of the UEA as an index. It can be configured to call this specific HOAS in the IMS (or CS) domain to indicate the need to switch, or let the HOAS judge whether it is a message to notify switching through a certain message format or information carried in the message;

Step 402: HOAS checks whether the user is allowed to switch from UMTS CS to IMS (this check can also be performed in HSS (Home Subscriber Server, Home Subscriber Server)). If handover is allowed, then find the corresponding CAP dialogue according to the user number of the UEA, and then instruct the MSC to establish a call to the HOAS, which includes the number of the HOAS in the IMS domain;

Steps 403-404: After receiving the instruction, the MSC finds a suitable MGCF in the IMS domain, uses ISUP/TUP/BICC messages to establish a TDM bearer 453 to the IM-MGW controlled by the MGCF, and then the MGCF sends a session establishment request to the HOAS , carrying the bearer information of the MGCF and the user number of the UEA. After the HOAS receives it, according to the user number of the UEA, find the saved UEA bearer information, and negotiate with the MGCF (see 3GPP protocol TS 23.228 for the negotiation process), and establish the IP bearer 452 from the IM-MGW controlled by the MGCF to the UEA;

Steps 405-406: After the bearers 452 and 453 are established, the HOAS instructs the MSC through the CAP dialogue to connect the TDM1 bearer 451 of the MSC<=>UEB with the TDM2 bearer of the IM-MGW controlled by the MSC<=>MGCF; connect the MSC<=> => CS radio bearer 450 of UEA_cs is released.

In this way, the bearer on the entire call chain through the IMS domain is established: 452-453-451. The situation after switching is shown in Figure 4B. At the same time, the HOAS collects the charging information of the CS domain through the CAP, and collects the charging information of the IMS domain through Diameter (a kind of AAA protocol), and associates the two charging information.

Steps 430-431: If UEA judges that it is necessary to switch back to CS, then UEA_ims will send a notification request to HOAS to switch back to CS through the established session in the IMS domain. The destination number is the number of HOAS in the IMS domain, and the user with UEA Number;

Steps 432-433: After the HOAS receives it, it finds that the terminal already has a CAP session with the MSC, but there is no call from the MSC to the CS domain of the UEA_cs, and instructs the MSC to establish a call to the UEA_cs. After the MSC receives it, it establishes a CS radio bearer 454 between the UEA_cs and the MSC through the call termination process in the CS domain;

Steps 434-435: After the call from the MSC to the UEA_cs is established, a notification will be sent to the HOAS, and the HOAS will indicate to connect the bearers 454 and 451;

Steps 436-438: HOAS instructs MSC to release bearer TDM2 453, instructs MGCF to release IP bearer 452, and releases corresponding signaling at the same time.

Thus, the call is switched back to CS.

Fig. 5 is a flow chart of the dual-mode terminal UEA calling PSTN user UEB, UEA switching from the IMS domain to the CS domain and switching back to the IMS domain, the steps are as follows:

First, UEA_ims is registered in the IMS domain. If the user subscribes for CS and IMS handover in HSS, then during the registration process, the number in the IMS domain of the HOAS responsible for CS/IMS handover may be brought to CSCF or UEA. The CSCF and UEA can also obtain the number in the IMS domain of the HOAS through local configuration or other methods. After that, UEA_ims initiates a call request to the IMS domain, and the destination number is the user number of UEB, with the user number of UEA, and possibly with the number in the IMS domain of HOAS. After the call request is routed to the CSCF, according to the filter rules (such as checking whether the user has the attribute of subscribing to the inter-domain handover service, or whether it has a HOAS number), the call request will be routed to the HOAS responsible for CS/IMS handover. After the HOAS receives it, it saves the corresponding relationship between the user number of UEA and the Session (transaction), and then initiates a call-initiating process to establish a call to UEB (PSTN user) through MGCF1. The bearer is divided into two sections, the IP bearer 550 from the UEA to the IM-MGW controlled by the MGCF1 and the TDM bearer 551 from the IM-MGW controlled by the MGCF1 to the UEB. The call information of the IMS domain saved in the HOAS includes the session ID of the incoming call and the outgoing call, the bearer information of the two calls, and the routing table to the destination, etc. The situation before handover is shown in Fig. 4C.

Steps 500-501: UEA finds that the call needs to be handed over to the CS domain according to certain criteria, so UEA_cs initiates a call from the CS domain, the destination number is the number of the HOAS in the IMS domain, and establishes a CS radio bearer 552 to the MSC;

Steps 502-503: MSC triggers the Camel service according to the destination number in the calling process, sets up the CAP dialogue 502 to the HOAS, and the subscriber number with UEA (the Camel data of the subscriber is inserted into the MSC/VLR database from the HLR when the subscriber's location is updated middle). After the HOAS is received, check whether the call is allowed to be handed over from IMS to CS. If allowed, save the corresponding relationship between the user number of the UEA and the CAP dialogue, and then instruct the MSC to establish a call from the MSC to the HOAS, and the indication includes the number of the HOAS in the IMS domain;

Steps 504-505: After receiving the instruction, the MSC selects a certain MGCF2, and establishes a TDM bearer 553 between the MSC and the IM-MGW controlled by the MGCF2. Then MGCF2 sends a call request to the HOAS, carrying the bearer information of MGCF2 and the user number of UEA. After the HOAS receives the bearer information, it saves the bearer information, finds the corresponding session in the IMS domain according to the user number of the UEA, then exchanges and negotiates the bearer information of MGCF1 and MGCF2, and establishes the IM-MGW controlled by MGCF1 and the IM-MGW controlled by MGCF2. IP bearer 554.

Steps 506-507: After the bearers 553 and 554 are established successfully, the HOAS instructs to release the IP bearer 550 and related signaling from the IM-MGW controlled by the MGCF1 to the UEA_ims. In this way, the following bearer is established between UEA_cs and UEB: 552-553-554-551, and the call is switched to the CS domain. The situation after switching is shown in Figure 4D.

In this process, the HOAS collects the charging information of the CS domain through the CAP, collects the charging information of the IMS domain through the Diameter, and associates the two charging information.

Steps 530-531: When UEA detects that the voice call needs to be switched back to IMS from CS, it first initiates registration from IMS, and then UEA_ims initiates a call request from the IMS domain, and the destination number is the number of HOAS in the IMS domain, with UEA at the same time The MSISDN number and bearer information in the IMS domain. The call request is routed to the HOAS according to the number of the HOAS in the IMS domain;

Steps 532-533: After receiving the request, the HOAS finds its session to UEB according to the user number of UEA, and then exchanges and negotiates bearer information with MGCF1, and establishes IP bearer 555 after success. In this way, bearers 555-551 are established from the IMS domain between UEA_ims and UEB;

Steps 534-536: After the bearers 555-551 are successfully established, the HOAS finds the corresponding CAP dialogue according to the user number of the UEA, and then notifies the MSC to release the call from the MSC to the HOAS and the CS call from the MSC to the UEA-cs, and release the call from the MSC to the HOAS. CAP dialogue.

In this way, the voice call is switched back to the IMS domain.

Above-mentioned two examples have solved the problem that dual-mode (UMTS CS and IMS) mobile phone carries out voice switching between UMTS CS domain and IMS domain. However, the present invention is not limited to switching between the two domains, nor is it limited to switching voice services. When switching between other domains, or when the domain structure changes, the call control process and equipment, bearer mode and equipment involved in the above process, as well as the establishment of inter-domain signaling and bearer should be changed according to relevant standards. However, the basic process of realizing inter-domain seamless switching in the present invention is still valid.

Claims (17)

1, the method for switching between the territory in a kind of communication system may further comprise the steps:

(a) in the system that comprises first and second territories at least, the territory switch controller that at least one all can be routed to is set, in these two territories to inserting these two territories and the terminal A of the service switchover between the territory of having contracted, for it specifies same territory switch controller;

(b) terminal A is initiated to the calling of other terminal from first territory, be established to the signaling link and the bearing link of other terminal by first territory, in call establishment, also set up the signaling contact of first territory and described territory switch controller, described territory switch controller preserve terminal A to first territory, first territory is to the call information of other terminal, be associated with the number of terminal A;

(c) terminal A detects in the time of need switching to second territory, be initiated to the calling of described territory switch controller from second territory, set up terminal A to second territory, arrive the signaling contact of described territory switch controller again, notify described territory switch controller to switch the also number of carried terminal A;

(d) described territory switch controller notified after, when allowing to switch on inspection, the inter-domain call between first territory, second territory is created in indication first or second territory, and according to the number of terminal A the calling to other terminal couples together to calling, inter-domain call and first territory in second territory with terminal A, finally set up terminal A to second territory, again to first territory, arrive the signaling link and the bearing link of other terminal again, preserve the call information of described three sections callings and the number by terminal A is associated at described territory switch controller;

(e) switch controller indication in described territory discharges signaling link and the bearing link of first territory to terminal A, and keeps and the signaling in first territory is got in touch, and terminal A switches to second territory from first territory.

2, the method for claim 1 is characterized in that, described step (e1) back is further comprising the steps of:

(f) terminal A detects when needing to switch go back to first territory, notifies described territory switch controller to switch the number of carried terminal A;

(g) calling of first territory to terminal A set up in switch controller indication in described territory, finds calling and the connection of already present first territory to other terminal according to the number of terminal A, sets up terminal A to first territory, arrive the signaling link and the bearing link of other terminal again;

(h) indication of described territory switch controller discharge second territory to first territory, second territory is to signaling link and the bearing link of terminal A, terminal A switches back to first territory from second territory.

3, the method for claim 1 is characterized in that, terminal A can also insert the 3rd territory, and the service switchover and be assigned to described territory switch controller of having contracted in this territory between the territory, and is further comprising the steps of in described step (e) back:

(f ') terminal A detects needs follow-up the 3rd territory that switches to, be initiated to the calling of described territory switch controller from the 3rd territory, set up terminal A to the three territories, arrive the signaling contact of described territory switch controller again, notify described territory switch controller to switch the also number of carried terminal A;

(g ') is after described territory switch controller is notified, when allowing to switch on inspection, the inter-domain call between first territory, the 3rd territory is created in indication the first or the 3rd territory, and the calling to other terminal of calling, inter-domain call and first territory in terminal A to the three territories is coupled together according to the number of terminal A, finally set up terminal A to the three territories, again to first territory, arrive the signaling link and the bearing link of other terminal again, preserve the call information of described three sections callings and the number by terminal A is associated at described territory switch controller;

The indication of (h ') described territory switch controller discharges signaling and the bearing link of second territory to terminal A, second territory to first territory, and terminal A finishes from the switching in three territories, second territory to the.

4, as claim 1,2 or 3 described methods, it is characterized in that, described two territories are meant universal mobile telecommunications system circuit commutative field and IMS domain, and described territory switch controller in described universal mobile telecommunications system circuit commutative field as service control point, in described IMS domain as application server.

As claim 1,2 or 3 described methods, it is characterized in that 5, described territory switch controller also is responsible for the charge information of collection terminal A in first territory and second territory, and the charge information in these two territories is associated.

6, method as claimed in claim 2, it is characterized in that in the described step (f), terminal A is by be initiated to the calling of described territory switch controller in first territory, perhaps utilize the signaling contact of arriving described territory switch controller in original second territory, notify described territory switch controller to switch.

7, as claim 1,2 or 3 described methods, it is characterized in that, when described territory switch controller couples together two sections callings,, also earlier exchange and consult the beared information of these two callings mutually the IP carrying.

8, the method for claim 1 is characterized in that, in the described step (c), when terminal A notifies described territory switch controller to switch, also carries the beared information of terminal A in second territory.

9, method as claimed in claim 4, it is characterized in that, in the described step (a), when terminal A is initiated to the calling of other terminal from described circuit commutative field, it is the customization application process that is triggered to the mobile network enhancing logic of described territory switch controller by first territory, set up the applying portion dialogue, realize what mutual signaling was got in touch.

10, method as claimed in claim 4, it is characterized in that, in the described step (a), when terminal A is initiated to the calling of other terminal from described IMS domain, call server controlled function in this territory is according to whether carrying the number of described territory switch controller in this territory in this calling, perhaps whether this user has the attribute of service switchover between signatory territory, determine whether routing the call to described territory switch controller, the number of described territory switch controller in IMS domain brings terminal A or call server controlled function by enrollment process, perhaps at terminal A or/and the local configuration of call server controlled function.

11, method as claimed in claim 4, it is characterized in that, in the described step (d), no matter terminal A need switch to IMS domain from the universal mobile telecommunications system circuit commutative field, perhaps opposite, described territory switch controller all is that the mobile switching centre of indication universal mobile telecommunications system circuit commutative field initiates cross-domain call, is destination Mobile Station International ISDN Number with described territory switch controller at the number of IMS domain.

12, the territory switch controller in a kind of communication system is characterized in that, comprises switching controls module, message processing module, wherein:

Described switching controls module further comprises: inspection unit, be used for when terminal request is switched, checking its business datum, and judge whether to allow to switch; Call out creating unit, be used in reference to be shown in and create a new calling on the territory that will switch to, perhaps create a new cross-domain call; Call out releasing unit, be used for after switching is finished, indicating discharging signaling and the bearing link that terminal is arrived in former territory;

Described message processing module is used for preserving the relevant information that call out in two territories, and according to the call information of the related same user of the number of terminal in two territories.

13, territory as claimed in claim 12 switch controller is characterized in that, also comprises information storage module, is used to preserve attribute of user data and business datum, comprises the whether attribute of service switchover between signatory territory of user, is used to judge whether allow to switch.

14, territory as claimed in claim 12 switch controller is characterized in that, also comprises accounting module, is used to collect the charge information in two territories and is associated with respective call.

15, territory as claimed in claim 12 switch controller is characterized in that described switching controls module also comprises the bearer negotiation unit, is used between two callings exchange and negotiating bearer information mutually.

16, a kind of communication system of switching between the territory realized, comprise terminal and first territory and second territory that can intercommunication, it is characterized in that, also comprise at least one territory switch controller, this territory switch controller basis routing mode separately in first and second territories can both be routed to

Described territory switch controller comprises switching controls module and message processing module, this switching controls module is used to judge whether allow to switch, indication is created in the territory on certain territory or the calling between the territory, indication discharges signaling and the bearing link of former territory to terminal after switching, and exchanges mutually and negotiating bearer information between two callings; This message processing module is used for preserving the relevant information that call out in two territories, and according to setting the call information of the same user of rule association in two territories;

Described terminal is a dual-mode terminal, can insert first territory and second territory, and can select a kind of access way automatically, and when calling on having a certain territory or session, this terminal can be initiated registration and session in another territory simultaneously, or calls out.

17, system as claimed in claim 16, it is characterized in that, described two territories are meant universal mobile telecommunications system circuit commutative field and IMS domain, and described territory switch controller in described universal mobile telecommunications system circuit commutative field as service control point, in described IMS domain as application server.

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