WO2006099814A1 - A method for setting up the call route from a circuit switched network to an ims network and a number translating entity - Google Patents

Abstract

A method for setting up the call route from a circuit switched network to an IMS network and a number translating entity. The method sets the function of translating the E.164 number to SIP-URI for the function entity in IMS network, and the method also comprises that A, E.164 number carried in the call is translated to SIP-URI by the function of translating the E.164 number to SIP-URI on said function entity and the SIP message including the translated SIP-URI is constructed and sent to I-CSCF, after MGCF has received the call from UE of the circuit switched network including the E.164 number for indicating the called UE; B, I-CSCF queries the route information saved by HSS to obtain the route information of called UE which is the one indicated by SIP-URI carried by the SIP message, the SIP message is sent to the called UE according to the route information of the called UE, and the called UE and calling UE negotiate about the SIP session to achieve the call.

Description

 Circuit switching network to IMS network call routing establishment method and number conversion entity

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for establishing call routing in an Internet Protocol Multimedia Subsystem (IMS) network, and more particularly to a method for establishing a call routing network to an IMS network call route and a number conversion entity. Background of the invention

 With the development of broadband networks, mobile communications are not limited to traditional voice communications, but can also combine multiple media services such as audio, video, pictures and text. A variety of media services can meet the diverse needs of user equipment (UE) by combining data services such as presence, short message, web page browsing, location information, push service (PUSH), and file sharing.

 Driven by various data service applications, standards organizations such as 3GPP and 3GPP2 have successively launched IMS architectures. The purpose is to implement a variety of multimedia service applications using a standardized open architecture in mobile networks, providing more to the UE. Choice and richer feelings.

In the 3GPP Release 5 (R5, Rdease) phase, IMS is introduced, which is superimposed on the packet domain network, by Call Control Function (CSCF), Media Gateway Control Function (MGCF), Media Resource Function (MRF) and Home Subscriber A functional entity such as a server (HSS). The CSCF can be further divided into three logical entities: S-CSCF, Proxy CSCF (P-CSCF) and Query CSCF (I-CSCF). The S-CSCF is a service switching center of the IMS, performs session control, maintains session state, is responsible for managing UE information, and generates charging information. The P-CSCF is an access point for the UE to access the IMS, completes UE registration, and is responsible for service quality ( QoS) control and security management; I-CSCF is responsible for interworking between IMS domains, managing the allocation of S-CSCF And selection, hiding network topology and configuration, generating billing data, etc. The MGCF controls the gateway to implement interworking between the IMS and other networks. MRF provides media resources. The HSS stores subscription data, configuration information, and the like of the UE.

 In IMS, the Session Initiation Protocol (SIP) is used as the signaling control protocol for IP multimedia sessions; the Diameter protocol is used for information exchange between the HSS and the I-CSCF and the Cx interface between the HSS and the S-CSCF.

 The IMS is applied in a packet network, a wireless local area (WLAN) network, or a next generation (NGN) network defined in 3GPP2.

 When the UE wants to access the IMS, it must use the public user ID to register with the IMS network side. The public user ID is used to identify the UE in the IMS network. The public user identifier can use the Uniform Resource Identifier for the Session Initiation Protocol (SIP- URI, Session Initiation Protocol Uniform Resource Indentifier ). A UE may have one or more public user identities.

The IMS network specification states that in an IMS network, the conversion of E.164 numbers from the circuit switched network to SIP-U I is done in the S-CSCF. When the S-CSCF receives the SIP message with the Request-URI (Request-URI), it will map the E.164 number in the format of "tel:URI" in the Request-URI header to the pre-set phone number (ENUM). The DNS translation function is translated into a SIP-URL that identifies the UE that can be routed in the IMS network. If the conversion on the S-CSCF is unsuccessful, the corresponding SIP message is likely to be routed to the circuit-switched network, by the circuit-switched network. For further processing, it is returned to the calling UE that initiates the SIP message, a notification message. Here, the database of the preset E UM DNS translation function is set by the IMS network operator according to the configuration of the UE in the IMS network. The ENUM DNS translation function corresponds to a series of URIs for the E.164 number, making the internationally uniform E.164 telephone number a network address resource that can be used in the IMS network. This implementation only considers that the SIP message is initiated by the calling UE in the IMS network, and the SIP message is used to indicate that the called UE's Request-imi is filled with an E.164 number. However, when the SIP message is initiated by the calling UE in the circuit interaction network, and the called UE is the UE in the IMS network, there is a technical problem in using this implementation method to complete a SIP session.

 Currently, the SIP session process between the calling UE of the circuit switched network and the called UE in the IMS network is: First, the calling UE initiates a call in the circuit switched network, such as initiating an initial address message (IAM, initial address) Message ) message, the call carries the E.164 number identifying the called UE information; secondly, since no functional entity in the circuit switched network has the ENUM DNS translation function for E.16 number to SIP-URI conversion, the call It will be sent to the MGCF in the home IMS network where the called UE is located. When the MGCF receives the call from the circuit switched network, it constructs a SIP INVITE message carrying the E.164 number identifying the called UE information and sends it to the I. -CSCF; again, the I-CSCF to the HSS queries the S-CSCF currently serving the called UE according to the called UE information carried in the SIP INVITE message, and routes the SIP INVITE message to the determined S-CSCF; Finally, the SIP INVITE message is further forwarded by the S-CSCF to the called UE, and the calling UE and the called UE perform a SIP session negotiation process. '

 Figure 1 is a flow chart of call setup signaling from a circuit-switched network to an IMS network as specified in the IMS network specification. It is assumed that the circuit-switched network is a public switched telephone network (PSTN). The specific steps are as follows:

 Step 100: The PSTN sends a ϊΑΜ message to the MGCF, where the message carries a relay identifier 'and a destination information that can be called to the called UE.

 Step 101: After receiving the message, the MGCF establishes a connection from the PSTN to the packet switched network through the H.248 command on the bearer plane.

Step 102: The MGCF constructs a SIP INVITE message, where the media description information is included. Subsequent routing to the S-CSCF to the S-CSCF (SS routing process).

 Step 103: Through the S-S routing process, the MGCF receives an acknowledgement (Offer Response) message carrying the capability of the called UE media stream, that is, obtaining the media stream capability of the called UE on the signaling plane.

 Step 104: The MGCF modifies the connection parameters by using a command and instructs the MGW to reserve resources required for the session.

 Step 105: The MGCF determines the media resource required for the session, and confirms the Offer Response message in step 103, and returns a message of the local reservation (Response Conf), that is, the confirmation message of the Offer Response to the peer.

 Step 106: The peer returns a response message (Conf Ack), that is, a confirmation message of the Response Conf message.

 Step 107: The media gateway (MGW) in the circuit switched network reserves resources.

 Step 108: After the resource reservation is completed, the MGCF returns a message for successfully reserving resources (Reservation Conf) to the peer. '

 Step 109: The peer returns a response message (Reservation Ornf) to the MGCF.

 Step 110: Perform a ringing process on the peer end.

 Step 111: The MGCF forwards an address completion message (ACM, Address Complete Message) to the PSTN network.

 Step 112: After the peer end responds, the MGCF will receive the SIP 200 OK message sent by the called UE as the final response.

 Step 113: The MGCF forwards an answer message (ANM, Answer Message) to the PSTN. Step 114: The MGCF notifies the MGW that the transmission of the media stream can be started by using the H.248 command.

 Step 115: The MGCF' returns an acknowledgement message to the SIP 200 OK SIP ACK:.

The SS routing process mentioned here refers to how the S-CSCF will SIP in the IMS 'Network' The process of routing messages to the called UE, as shown in FIG. 2, FIG. 2 is a signaling diagram of the SS routing process when the call is terminated. The Exit Gateway Control Function (BGCF) is the interface between the S-CSCF and the PSTN network. For detailed description, refer to TS 23.228, Section 5.5.3. Each step in FIG. 2 can be connected to the steps described in FIG. 1. According to the current IMS specification, the MGCF is regarded as an S-SCSF in the IMS network, and therefore, if the translation is performed, the ^p lUE is The S-CSCF located in the PSTN network, and the S-CSCF located in the home IMS network where the called UE is located in FIG. 2 is considered to be the MGCF that receives the PSTN network call.

 In the existing IMS specification, the MGCF is regarded as an MGCF with the same status as the S-CSCF in multiple descriptions and process descriptions. The only difference is that the MGCF does not trigger service control, and supports circuit-switched network signaling and SIP packets. The conversion between orders. However, according to the status and implementation functions of the MGCF, the MGCF should be more like a P-CSCF than an S-CSCF. This is because there are many S-CSCF functions that cannot be implemented by the MGCF. For example, the S-CSCF needs to be saved. The subscription information of the IMS user is not saved on the MGCF; the S-CSCF saves the routing information addressed to the called UE, and l is not saved on the lGCF. Therefore, from the perspective of signaling routing, the status of MGCF S-CS.CF ' is different.

 Since the MGCF does not store the subscription information and routing information of the user's as the S-CSCF, it cannot directly route the relay identifier and destination information carried in the message according to FIG. 1 from the PSTN to the BGCF or P- in the IMS network. The CSCF, which is further routed to the called UE, establishes a call.

 In order to establish a call, the MGCF must first route to the I-CSCF, and the I-CSCF queries the HSS that pre-stores the subscription information of the IMS network user, thereby obtaining routing information to the called UE having the relay identifier and the destination information, and then rerouting. To the called UE, but because the MGCF can not trigger service control and cannot be routed to the I-CSCF, it cannot be implemented in this way.

Further, due to call signaling sent from the circuit switched network, such as IAM carrying Can only be used for the identification of relay identification and destination information identified in the circuit-switched network.

E.164 number, not the SIP-URI that can be identified in the IMS network to identify the destination information. Therefore, even if the MGCF can route to the I-CSCF, it cannot query the routing information of the called UE according to the E.164 number. Thus, the call setup process from the circuit switched network to the IMS network fails.

 It can be seen from the above analysis that there are some misunderstandings in locating the MGCF. When the call from the circuit-switched network is routed in the IMS network, the following problems exist, which leads to the current routing process being impossible, and Business processing also has an impact.

 1. Since the MGCF does not store the subscription information of the IMS network user, it cannot decide to route the call from the circuit switched network to the BGCF or the P-CSCF as the S-CSCF, and further routes to the called UE.

 2. Since the MGCF cannot be routed to the I-CSCF to query the subscription information of the called UE, it is further impossible to query the routing information of the called UE according to the E.164 number used to indicate the relay identifier and the destination information, so that it is impossible to know. Which S-CSCF is currently serving the called UE, and therefore cannot directly address the S-CSCF serving the called UE, thereby making it impossible for the S-CSCF to perform subsequent procedures. '

 3. It is assumed that the MGCF can route the call from the circuit-switched network to the BGCF or the P-CSCF for further processing to the called party. However, this will omit the service control of the S-CSCF serving the called UE. The process, and the S-CSCF, as a service node in the IMS network, cannot be omitted, otherwise it will cause problems in charging and security.

 In summary, the establishment of call routing from the circuit switched network to the IMS network is currently not possible. Summary of the invention

In view of this, the main object of the present invention is to provide a method for establishing a call routing network to an IMS network call route, which can implement a circuit switched network to an IMS network call. The establishment of a route.

 The present invention also provides a number translation entity that can convert an E.164 number into a SIP-URI, thereby enabling the establishment of a circuit switched network to IMS network call routing.

 According to the above object, the technical solution of the present invention is achieved as follows:

 A method for establishing a circuit switching network to an internet protocol multimedia subsystem IMS network call routing, characterized in that a function of setting a E.164 number into a session initiation protocol uniform resource identifier SIP-URI for a functional entity in an IMS network , the method also includes:

 A. The physical gateway control function MGCF receives the call from the calling user equipment UE in the circuit switched network carrying the E.164 number indicating the called UE, and then goes to the functional entity to pass the E.164 number. Converting to SO JRI function converts the belonging number into a SIP-URI, constructs a session initiation protocol SIP message carrying the converted SIP-URI, and sends it to the query call control function I-CSCF;

 B. The I-CSCF queries the home subscriber server HSS to obtain the routing information of the called UE indicated by the SIP-URI carried in the saved SIP message, and sends the SIP message to the called UE according to the routing information of the called UE, and is called. The UE and the calling UE perform a SIP session negotiation process to complete the current call.

 The functional entity is MGCF or I-CSCF.

 When the function entity is an MGCF, the process of constructing the SIP message in step A is: filling the SIP-URI into the Request-URI field in the constructed SIP message.

 When the functional entity is an I-C CF, the process of constructing the SIP message in step A is:

The MGCF generates a SIP message carrying the telephone uniform resource identifier tel-URI formed by the E.164 number, and sends the SIP message to the I-CSCF;

The I-CSCF replaces the tel-URI formed by the E.164 number in the SIP message with the SIP-URI. The process of generating a SIP message carrying a tel-URI consisting of an E.164 number is: Filling the E.164 number into the Request-URI in the constructed SIP message in the "tel:URT format" In the field;

 The process of replacing the tel-URI formed by the E.164 number in the SIP message with the SIP-URI is: replacing the td-URI in the Request-UKI field in the constructed SIP message with the SIP-URI.

 The process of sending the SIP message to the called UE in step B is:

 The I-CSCF queries the routing information of the UE saved by the HSS according to the SIP-URI carried by the SIP message, determines the serving call control function S-CSCF that provides the service for the called UE, and learns the route to the S-CSCF, which will be constructed. Sending a SIP message to the S-CSCF;

 The S-CSCF establishes a route to the called UE according to the SIP-URI carried in the received SIP message, and sends the SIP message to the called UE.

 After the E.164 number carried in the call is converted into a SIP-URI, the method further includes:

 The functional entity determines whether the success is ii. E.164 is converted to a SIP-URI function to convert the E.164 number carried by the call into SIP-U T. If yes, perform the subsequent steps; otherwise, it will return to carry The response to the error message is sent to the circuit switched network, processed by the circuit switched network or the call error message is sent to the calling UE in the circuit switched network.

 When there is more than one HSS in the IMS network, and more than one HSS is managed by the subscription location server SLF, before the method of querying the HSS of the called UE subscription information in step B, the method further includes:

 The I-CSCF queries the SLF according to the SIP-URI carried by the SIP message, determines the HSS storing the information of the called UE with the SIP-URI, and then performs a query for the HSS storing the routing information of the called UE.

The SIP message described in step A; έ is sent to i-CSCF ^: the process is ':

 The I-CSCF address is set in advance in the MGCF, and the MGCF sends the SIP message to the I-CSCF corresponding to the address according to the set I-CSCF address;

Or set an I-CSCF list in the MGCF in advance, according to the rules set by the MGCF. Then select an I-CSCF from the I-CSCF list and send the SIP message to the selected I-CSCF.

 The function of converting the E.164 number into a SIP-URI is the ENUM DNS translation function; or to set the correspondence between the E.164 number and the SIP-U I, and converting the E.164 number into a SIP-URI according to the correspondence relationship. The function.

 The MGCF is an MGCF to which the called UE belongs to the IMS network.

 When the MGCF is not the MGCF of the IMS network, the process of the MGCF sending the SIP message to the I-CSCF is:

 The MGCF and the called UE's topology hidden interworking gateway I-CSCF (THIG) in the home IMS network perform signaling interaction, obtain the 1-CSCF that performs the query function, and then send the SIP message to the obtained I-I that performs the query function. CSCF.

 The I-CSCFC TH1G) and the I-CSCF performing the query function are the same I-CSCF. Setting routing information in the MGCF, the method further includes:

 The MGCF receives the call signaling sent by the contending UE from the circuit switched network, converts the call signaling into a SIP message, and sends the converted SIP message to the called UE according to the routing information set by the MGCF.

 The routing information is set corresponding to the session identifier;

 The MGCF also sets a correspondence between the session identifier and the connection information carried by the call signaling from the circuit switched network;

The call signaling from the circuit-switched network carries ^: connection information of the circuit-switched link; the process of transmitting the converted SIP message to the called UE according to the set routing information is: the MGCF determines according to the set correspondence relationship The connection information carried by the call signaling corresponds to a session identifier, and the routing information is determined according to the session identifier, and the converted SIP message is sent to the called UE according to the determined routing information.

The routing information is a service call control function that is served by the MGCF for the called UE. Routing information from the S-CSCF to the called UE.

 The process of setting routing information in the MGCF is:

 Setting a correspondence between a telephone uniform resource identifier tel-URI formed by an E.164 number of the UE and a uniform resource identifier SIP-URI for the session initiation protocol of the UE in the HSS of the IMS network;

 The MGCF in the home IMS network of the called UE receives the call signaling from the E.164 number of the called UE initiated by the calling UE in the circuit switched network, and constructs a tel consisting of the E.164 number carrying the called UE. - the session initiation protocol SIP message of the URI is sent to the inquiry call control function I-CSCF;

 The I-CSCF queries the correspondence between the HSS settings, and obtains the SIP-URI corresponding to the tel-URI formed by the E.164 number of the called UE in the SIP message, and obtains the routing information of the called UE according to the routing information of the UE saved by the HSS. The routing information is carried in the response message returned to the MGCF, and the routing information is stored by the MGCF.

 The process of setting routing information in the MGCF is:

 The function of converting the E.164 number to the SIP-URI is set to the MGCF in the IMS network;

After receiving the call signaling from the circuit-switched network carrying the E.164 number indicating the called UE, the MGCF converts the E.164 number into a SIP-URI function to carry the call signaling. Converting the .164 number to a SIP-URI, constructing a SIP message carrying the converted SIP-URI and transmitting it to the I-CSCF;

 The I-CSCF queries the routing information of the UE that is saved by the HSS, and obtains the routing information of the called UE that has the SIP-URI carried by the SIP message. The routing information is carried in the response message returned to the MGCF, and the routing information is stored by the MGCF.

 Before the sending the converted SIP message to the called UE according to the routing information set by the MGCF, the method further includes:

The MGCF determines that the SIP message converted by the call signaling is not a session-independent SIP message. The step of transmitting the converted SIP message to the called UE according to the routing information set in the MGCF is performed.

 Before the sending the converted SIP message to the called UE according to the routing information set by the MGCF, the method further includes:

 The MGCF determines the routing information corresponding to the SIP message to which the call signaling is set, and performs the step of transmitting the converted SIP message to the called UE according to the routing information set in the MGCF.

 The routing information is set corresponding to the user identifier of the called UE; the call signaling from the circuit switched network carries the user identifier of the called UE; and the routing information set by the data is converted into the SIP The process of sending the message to the called UE is: The MGCF determines the routing information of the called UE according to the user identifier of the called UE carried in the call signaling, and sends the converted SIP message to the called UE according to the determined routing information.

 The user ID of the called UE is an E.164 number identifying the called UE in the circuit switched network or a URI of the called UE in the IMS network, the URI being a SIP-URI or a Tel-URL to be used in the circuit The switching network identifies the E.164 number of the called UE and the URI used to identify the called UE in the IMS network.

 The entity includes a function module for converting the E.164 code to SIP-liRI and a module for constructing a SIP message, and the number conversion entity transmits the E.164 number carried by the call to itself to convert the E.164 number to SIP. The function module of the URI is converted into a SIP-URI and sent to the module constructing the SIP message. The module constructing the SIP message constructs the SIP message carrying the converted SIP-URI, and then sends the SIP message.

 The entity is an MGCF or an I-CSCF.

The functional module for converting the E.164 number into the SIP-URI is the ENXJM DNS translation function module or has a correspondence between the E.164 number and the SIP-URI. As can be seen from the foregoing solution, the present invention pre-sets the function of converting the E.164 number into the SIP-U I in the MGCF or the I-CSCF in the IMS network. When the IMS network receives the call from the circuit-switched network, the MGCF is adopted. Or the function of converting the E.164 number of the I-CSCF to the SIP-URI converts the E.164 number carried by the call into a SIP-URI that can be routed in the IMS network, constructs the SIP message by using the converted SIP-URI, according to the conversion The subsequent SIP-URI to the I-CSCF queries the routing information of the called UE. The I-CSCF determines the route through the S-CSCF serving the called UE to the called UE by querying the HSS, and sends the SIP message to the S-CSCF through the S-CSCF. Called UE. The called UE and the calling UE that have received the SIP message perform a SIP session negotiation process to complete the current call. The method provided by the invention realizes the establishment of call routing from a circuit switched network to an IMS network.

 Further, in order to alleviate the service burden of the IMS network, the present invention sets the correspondence between the routing information corresponding to the session identifier and the connection information carried by the session identifier and the call signaling in the MGCF, when the MGCF receives the circuit switching network. After the call signaling, the routing information corresponding to the connection information carried by the call signaling is obtained according to the preset routing information, so that the SIP message of the call signaling conversion is routed to the called UE according to the routing information.

BRIEF DESCRIPTION OF THE DRAWINGS

 Figure 1 is a flow chart of call setup signaling from a circuit switched network to an IMS network as specified in the IMS network specification;

 Figure 2 is a signaling diagram of the S-S routing process when the call is terminated at the PSTN;

 3 is a signaling flowchart of establishing a call route from a circuit switched network to an IMS network by an I-CSCF according to the present invention;

4 is a flowchart of Embodiment 1 of a method for establishing call routing from a circuit switched network to an IMS network according to the present invention; 5 is a flowchart of Embodiment 2 of a method for establishing a call route from a circuit switched network to an IMS network according to the present invention;

 6 is a flow chart of a method for implementing a call process from a circuit switched network to an IMS network according to the present invention;

 7 is a signaling flowchart of the present invention for transmitting call setup signaling from a circuit switched network to an IMS network;

 8 is a signaling flowchart of the present invention for transmitting call release signaling from a circuit switched network to an IMS network;

 9 is a flow chart of call signaling for session-independent transmission of a converted SIP message from a circuit-switched network to an IMS network according to the present invention;

 10 is a flow chart of a method for transmitting call signaling from a circuit switched network to an IMS network according to the present invention;

 FIG. 11 is a schematic structural diagram of a number conversion entity according to the present invention. Mode for carrying out the invention

 The present invention will be further described in detail below with reference to the accompanying drawings.

 In order to implement the present invention, the MGCF must first route the call from the circuit switched network to the I-CSCF, so that the I-CSCF queries the HSS to obtain the subscription information and routing information of the called UE, and the I-CSCF will come from the circuit switched network according to the routing information. The call is routed to the S-CSCF that serves the called party, and is further routed to the called UE. For the call routing process from the S-CSCF serving the called UE to the network where the called UE is located, refer to the process described in FIG. 2. For the call routing process from the network where the called UE is located to the called UE, refer to TS 23.228. Correspond to the description of the chapter.

The present invention can pre-set the address of the I-CSCF in the MGCF, and wait until there is a slave circuit switching network. The call from the network is first routed to the SIP message with the call-converted I-CSCF with the pre-set I-CSCF address. The present invention may also not set the I-CSCF address in the MGCF, but set an I-CSCF list. After the MGCF waits for a call from the circuit switched network, select one from the I-CSCF list according to the set rule. The I-CSCF sends the SIP message converted by the call to the selected I-CSCF.

 FIG. 3 is a signaling flowchart of establishing a call route from a circuit switched network to an IMS network by an I-CSCF according to the present invention, where the specific process is:

 Step 300: A call is initiated by a calling UE of the circuit switched network, and the PSTN sends an IAM message to the MGCF in the IMS network.

 Step 301: The MGCF establishes a connection with the PST on the bearer plane by using an H.248 command.

 Step 302: The MGCF constructs a SIP INVITE message, and sends the constructed message to the I-CSCF.

 The I-CSCF may be an I-CSCF having an I-CSCF address preset by the MGCF, or an I-CSCF arbitrarily selected by the MGCF.

 Step 303: The I-CSCF sends a location query request (Location Query) to the HSS storing the subscription information of the called UE, and obtains routing information of the called UE.

 Step 304: The HSS returns the routing information of the called UE to the I-CSCF.

 Step 305: The I-CSCF determines, according to the routing information of the called UE, the S-CSCF that serves the called UE, further determines a route to the called UE, and sends a SIP INVITE message to the S-CSCF serving the called UE.

 Step 306 ~ Step 307: The S-CSCF serving the called l) E performs service control on the called UE and forwards the SliP INVITE message to the called UE through the next hop function entity according to the route to the called UE.

According to the prior art, the functional entity of the next hop of the S-CSCF and the terminating network of the current call have Off, when the call is terminated in the IMS network, the functional entity is a P-CSCF; when the call is terminated on the PSTN network, the functional entity is a BGCF.

 Steps 308-310: The called UE sends an Offer Response message to the S-CSCF, and the S-CSCF forwards the Offer Response message to the MGCF through the I-CSCF, where the message indicates the media stream capability of the called UE. ' . : ■

 Step 311: The MGCF modifies the connection parameter by using the H.248 command and instructs the MGW to reserve the resources required for the session.

 Steps 312 ~ 314, the MGCF determines the media resources required for the session that can be provided, and the MGCF follows the route to the S-CSCF and the route to the called UE, and the I-CSCF and the S-CSCF serving the called UE will Response Conf is forwarded to the called UE through the next hop function entity. '

 Steps 315 ~ 317, the called UE returns a Conf Ack to the MGCF via the S-CSCF and the I-CSCF serving the called UE.

 Step 318: The MGW reserves resources.

 Steps 319 ~ 321 After the resource reservation is completed, the MGCF forwards the Reservation Conf to the called UE through the next hop capable entity through the I-CSCF and the S-CSCF that provides the service to the called UE.

 Steps 322 - 324 > The called UE sends a response message (Reservation Conf) to the MGCF via the S-CSCF and the I-CSCF serving the called UE.

 Steps 325 ~ 327, the called UE performs a Ringing process by the S-CSCF and the I-CSCF that provide services for the called UE.

 Step 328: The MGCF forwards the ACM message to the PSTN network.

 Steps 329 ~ 331, after the called UE answers, the S-CSCF and the I-CSCF that provide services for the called UE send a SIP 200 OK message to the MGCF.

 Step 332: The MGCF sends an ANM message to the PSTN.

Step 333: The MGCF notifies the MGW to start the transmission of the media stream by using the 248.248 command. Steps 334 ~ 336, the MGCF returns an acknowledgement message SIP ACK to the SIP 200 OK via the I-CSCF and the S-CSCF serving the called UE.

 In the prior art, the call from the circuit-switched network carries the E.164 number used to identify the called UE information and the relay identifier. Since the IMS network does not support the E.164 number, the E.164 number must be converted. The SIP-URI supported by the IMS network can finally query the HSS for the routing information of the called UE with SIP-U I. Therefore, for the present invention, how to route to the I-CSCF to query the routing information of the called UE and how to convert the E.164 number carried by the call from the circuit switched network into the SIP-URI supported by the IMS network is indispensable. The following describes how to convert the E.164 number carried by the call from the circuit switched network to the SIP-URI supported by the IMS network.

 The present invention solves the problem in the prior art that a calling UE from a circuit switched network calls an IMS network by setting a function of converting an E.164 number into a SIP-URI in an MGCF or an I-CSCF in an IMS network, such as an ENUM DNS translation function. When the UE is called, the SIP message cannot be routed in the IMS network, and thus cannot be routed to the S-CSCF to which the called UE belongs and further routed to the called UE. Here, the database of the preset ENUM DNS translation function is set by the IMS network operator according to the matching condition of the UE in the IMS network. One of the ENUM DNS translation functions is to correspond to a series of U I for the E.164 number, so that the international unified E.164 telephone number becomes a network resource that can be used in the IMS network. In the prior art, the ENUM DNS translation function is set in the S-CSCF.

The function of converting the E.164 number to the SIP-URI set in the MGCF or the I-CSCF of the present invention may not be the E UM DNS translation function, but the correspondence between the set E.164 number and the SIP-URI, according to Corresponding relationship MGCF or I-CSCF converts E.164 number to SIP-URL. The following is an example of adding ENUM DNS translation capability in MGCF and adding ENUM DNS translation function in I-CSCF, respectively, to illustrate how the invention is established from a circuit switched network. Call routing for the IMS network. FIG. 4 is a flowchart of Embodiment 1 of a method for establishing a call route from a circuit switched network to an IMS network. The embodiment adds an E UM DNS translation function to the MGCF, and the specific steps are as follows:

 Step 400: The calling UE in the circuit-switched network initiates a call carrying an E.164 number, and the call is used to call a called UE in the IMS network, and the E.164 number carried by the call is used to indicate the user identifier of the called UE. .

 Step 401: The call initiated by the calling UE is sent to the MGCF in the IMS network to which the called UE belongs, through the circuit switched network, where the MGCF is an interworking gateway between the circuit switched network and the IMS network to which the called UE belongs.

 Step 402: After receiving the call, the MGCF in the IMS network of the called UE converts the E.164 number carried by the call into a SIP-URI by using the set ENUM DNS translation function, and constructs a SIP INVITE message according to the prior art. The message carries the converted SIP-U L converted SIP-URI as the public user identity used by the called UE in the IMS network. The method of constructing the SIP INVITE message is: Filling the converted SIP-URI into the Request-URI field of the SIP INVITE message, and then constructing the other words of the SIP INVITE message includes: setting the head of the Supported field to "lOOrel", inserting A P-Asserted-Identity header, which generates a unique IMS network charging identifier to be filled in the header of the P-Charging-Vector field, and fills in the header of the P-Charging-Vector header field with the parameter identifying the IMS network where the MGCF is located. Wait.

 Step 403: The MGCF in the IMS network to which the called UE belongs sends the constructed SIP INVITE message to the I-CSCF of the IMS network to which the called UE belongs.

Step 404: After receiving the SIP-URI carried by the message, the I-CSCF that receives the SIP INVITE message queries the HSS through the Cx interface message, and obtains the S-CSCF that provides the service for the called UE with the SIP-imi. The obtained road for the S-CSCF that provides service to the called UE By.

 The processing after the I-CSCF receives the SIP INVITE message is the same as the prior art.

Step 405, I-CSCF receives the SIP INVITE message transmits the message to the obtained S-CSCF serving the called UE ₀ is determined by the routing

 Step 406: After receiving the message, the S-CSCF that provides the service for the called UE determines the route to the called UE, and sends the message to the called UE.

 The processing after the S-CSCF receives the SIP INVITE message is the same as the prior art.

 Step 407: The calling UE and the called UE perform a SIP session negotiation process to complete the current call. The SIP INVITE message of the present invention is only an example. The MGCF can also construct other SIP messages. The common feature is that the MGCF converts the E.164 number carried by the call into a SIP-URI through the set ENUM DNS translation function. SIP message for SIP-U I. '

 In the present invention, the MGCF may also be an MGCF in any one of the IMS networks, and not necessarily the home IMS network in which the called UE is located. This is because, due to the policy considerations of the IMS network operator or the deployment of the IMS network, in some cases, the call initiated by the circuit switched network may first be sent to the MGCF in an IMS' network, but the IMS network is not necessarily The UE is called the home IMS network, so the MGCF needs to be further routed. In this case, the MGCF that is not the UE's home IMS network may need to first and the called UE belong to the I-CSCF in the IMS network to perform the topology hiding function, that is, the topology hidden interworking gateway (I-CSCF (THIG) The I-CSCF (Topology Hiding Inter-working Gateway) is contacted to obtain the I-CSCF that performs the query function, and then contacts the obtained I-CSCF that performs the query function to query the subscription information and routing information of the called UE. The I-CSCF and I-CSCF (THIG) that perform the query function can be the same I-CSCF or two independent I-CSCFs.

FIG. 5 is a flowchart of Embodiment 2 of a method for establishing call routing from a circuit switched network to an IMS network according to the present invention. This embodiment adds an ENUM DNS translation function to the I-CSCF, and the specific The steps are:

 Step 500: In the circuit switching, the calling UE of the network initiates a call carrying an E.164 number, and the call is used to call the called UE in the IMS network, and the E.164 number carried by the call is a number indicating the called UE.

 Step 501: The call initiated by the calling UE is sent to the MGCF in the IMS network to which the called UE belongs, through the circuit switched network, where the MGCF is an interworking gateway between the circuit switched network and the IMS network to which the called UE belongs.

 Step 502: After receiving the call, the MGCF in the IMS network to which the called UE belongs, constructs a SIP INVITE message according to the prior art, where the message carries a telephone uniform resource identifier (tel-) indicating the E.164 number of the called UE. URI ).

 The method of constructing the SIP INVITE message is as follows: The E.164 number indicating the called UE is filled in the SIP INVITE message ^ Request-URI field according to the "tel: URI" format, and then the other fields of the SIP INVITE message are constructed. These fields are defined in the existing IMS specification TS 23.228, including: setting the header of the Supported field to "lOOrel", inserting a P-Asserted-Identity header, and generating a unique IMS. The network charging identifier is filled in the header of the P-Charging-Vector field, and the parameters of the IMS network where the MGCF is located are filled in the header of the P-Charging-Vector header field.

 Step 503: The MGCF in the IMS network to which the called UE belongs sends the constructed SIP INVITE message to the I-CSCF of the IMS network to which the called UE belongs.

 Step 504: The I-CSCF detects that the message in the Request-URI field is "tel: the URL in the URT format means that the called UE uses an E.164 number, and the ENUM DNS translation function is set to "tel:URl". Convert the E.164 number in the SIP-URL

The converted SIP-URI is the public user identity used by the called UE in the IMS network. Step 505: The I-CSCF fills the converted SIP-URI into the message Request-URI field, and replaces the E.164 number indicating the called UE in the Request-URI field of the message. tel-URI.

 Step 506: After the converted SIP-URI, the I-CSCF queries the HSS through the Cx interface message to obtain an S-CSCF that provides the service for the called UE with the SIP-URI, and determines that the obtained UE is provided for the called UE. The route of the serving S-CSCF.

 Step 507: The I-CSCF sends the message to the obtained S-CSC1 serving the called UE through the determined route. .

 Step 508: The S-CSCF that provides the service for the called UE receives the SIP INVITE message, determines a route to the called UE, and sends the message to the called UE.

 The processing after the S-CSCF receives the SIP INVITE message is the same as the prior art.

 Step 509: The calling UE and the called UE perform a SIP session negotiation process to complete the current call. The SIP INVITE provided by the present invention is merely an example. For other SIP messages, the I-CSCF is also processed as such. '

 The function of converting the E.164 number to the SIP-URI is set in the MGCF or the I-CSCF. If the E.164 number carried by the call cannot be converted to the SIP-URI through the set, the pre-setting according to the IMS network can be performed. Returning the response carrying the error message from the circuit handover network to the circuit switched network, and further processing by the circuit switched network, or returning a call to the calling UE of the circuit switched network according to the error handling The invention of the error can be used to convert the E.164 number into the SIP-URI function in both the MGCF and the I-CSCF, but since the MGCF is the first functional entity after the call from the circuit switched network enters the IMS network, The function of converting the E.164 number to the SIP-URI in the MGCF can reduce the burden on the subsequent functional entities in the IMS network and simplify the implementation of the subsequent functional entities in the IMS network.

When there are multiple HSSs in the IMS network, I- 3⁄4Ct?f must first query the subscription location server (SLF, Subscription Locator Function) in the IMS network, which can be rooted in the query process. According to the SIP-URI of the called UE constructing the Dx interface message, the result of the query is the HSS storing the information about the called UE corresponding to the SIP-URI, and then the I-CSCF sends a Cx message to the HSS. The SIP-URI corresponds to the S-CSCF served by the UE.

 The method and the prior art provided by the present invention are relatively independent, that is, the existing S-CSCF supports the ENUM DNS translation function.

 The MGCF in the present invention can be not only the MGCF in the IMS network to which the called U3⁄4 belongs, but also the MGCF in any IMS network.

 The disadvantages of the prior art are solved by the method provided by the present invention: Since the present invention routes the call from the circuit switched network to the I-CSCF to query the routing information of the called UE and the E that can carry the call from the circuit switched network The .164 number is converted to a SIP-URI supported by the IMS network, so the call from the circuit switched network can be routed to the called UE through the S-CSCF serving the called UE, so that the called UE can be provided. The serving S-CSCF performs service control on the called UE, and completes charging and security management for the called UE.

 The method provided by the present invention can solve the problem that the calling UE of the existing circuit-switched network and the called UE in the IMS network cannot be routed to the called UE in the IMS network when the SIP session is established, and the TIMS network is improved. The application and application make the IMS network more mature, more adaptable to various network conditions in the specific implementation, and improve the user satisfaction level of using the UE.

Although the method provided by the above invention can realize the route establishment from the circuit switched network to the IMS network, there are still disadvantages: for each call signaling interaction in the call process from the circuit switched network to the IMS network, The above method establishes a route, that is, a function of converting a preset E.164 number into a SIP-URI to convert an E.164 number carried by the call signaling into a SIP-URI, and then determining, according to the SIP-URI, the ^pl ]UE The routing information is routed to the called UE by the S-CSCF serving the called UE according to the routing information I-CSCF of the called UE. Therefore, even if these call signaling is signaling during a call, the transmission must go back from the MGCF to the I-CSCF to the HSS and then back to the I-CSCF. The I-CSCF goes to the called UE to the S-CSCF that provides the service to the called UE. In this way, the call signaling interaction time from the circuit switched network to the IMS network is increased, and the service burden of the IMS network is increased.

 In order to overcome the above disadvantages, the present invention can also store routing information in the MGCF in the IMS network. When the MGCF receives the call signaling sent by the calling UE in the circuit switched network, the call signaling is converted into a session initiation protocol SIP message. The converted SIP message is sent to the called UE according to the routing information set by the MGCF. In this way, the method provided by the present invention can directly route call signaling to the called UE through the MGCF through the S-CSCF serving the called UE without the I-CSCF query, thereby reducing the call signal from the circuit switched network to the IMS network. Make interaction time and reduce the business burden of the IMS network.

 The present invention has two ways of storing routing information in the MGCF and performing subsequent processing according to the saved routing information. The following two methods are respectively described in detail.

 The first way.

 Since during the call from the circuit switched network to the IMS network, there is a high probability that multiple call signaling interactions associated with the call process will occur. The first call signaling interaction in the call process needs to be implemented by the method provided by the above invention, but the second call signaling interaction, the third call signaling interaction, and the last call signaling interaction do not need to be adopted. The method provided by the present invention, in the MGC, sets the routing information of the current call, that is, sets the routing information corresponding to the session identifier, and the routing information is obtained during the first call signaling interaction process of the call.

Since the first call signaling of the current call from the circuit switched network, that is, the call setup signaling carries the connection information, the information is used to indicate the circuit switched link, so the MGCF assigns the session identifier to the call according to the connection information. And storing routing information of the current call corresponding to the allocated session identifier. Therefore, after the subsequent call signaling from the circuit switched network is received by the MGCF, the session identifier may be determined according to the connection information carried in the subsequent call signaling. Thereby, the routing information corresponding to the session identifier is determined, and the determined routing information is directly routed to the called UE by the S-CSCF serving the called UE.

 The session identifier of the present invention may be the call identifier (Call lD) of this call. The routing information related to the current call set in the MGCF of the present invention is routing information from the MGCF to the S-CSCF serving the called UE and further routing information to the called UE.

 6 is a flow chart of a method for implementing a call process from a circuit switched network to an IMS network according to the present invention. A call process refers to an entire process from the establishment of a call to the maintenance of a call to the release of a call. The specific steps are as follows:

 Step 600: During a call, the calling UE of the circuit switched network initiates call setup signaling carrying the E.164 number of the called UE and the connection information to the called UE in the IMS network. ' ' ' ' ' Step 601: After receiving the call setup signal during the current call, the MGCF in the IMS network converts the call setup signaling into a SIP message according to the prior art method.

 Step 602: The MGCF in the IMS network determines whether the SIP message converted by the call setup signaling is a session-independent SIP message. If yes, go to step 603; otherwise, go to step 604.

 The mapping relationship between the call signaling and the SIP message in the circuit-switched network and whether the SIP message is session-independent or session-related SIP message is pre-stored in the MGCF. Therefore, the MGCF can determine the SIP message corresponding to the call signaling in the circuit switched network according to the mapping relationship, so that the SIP message is determined to be the session charge according to whether the SIP message is a session-independent or session-related SIP message. Whether the SIP message is a session-related SIP message. '

In the prior art, a session-related SIP message refers to a request message that establishes a session after receiving the corresponding response message, and retains the session state on each state node through which the message passes. The session can only be released after one of the User Agents (UAs) initiates a release request. A session-independent SIP message refers to a request message that completes the request after receiving the corresponding response message, and does not retain any information on each state node through which the message passes.

 Step 603: The MGCF in the IMS network sends the SIP message converted by the call setup signaling to the S-CSCF serving the called UE through the I-CSCF by using the route determined by the method provided by the foregoing method, and then is the called UE. The serving S-CSCF sends a SIP message converted by the call setup signaling to the called UE, establishes a connection between the calling UE and the called UE, and ends.

 Step 604: The MGCF in the IMS network sends the SIP message converted by the call setup signaling to the S-CSCF serving the called UE through the I-CSCF by using the route determined by the method provided by the foregoing method, and then is the called UE. The serving S-CSCF sends the SIP message converted by the call setup signaling to the called UE, and establishes a connection between the calling UE and the called UE;

And the MGCF stores the determined route of the S-CSCF serving the called UE to the called UE as the routing information of the current call, '^; the routing information of the current call corresponds to the session allocated for the call. The identifier is stored, and the allocation ^ session identifier corresponds to the connection information carried by the call setup signaling.

 Step 605: The calling UE of the circuit switched network initiates call signaling carrying the connection information and the E.164 number to the called UE in the IMS network.

 Step 605 and subsequent steps may also not follow step 604, but exist as a separate process.

 Step 606: After receiving the call signaling, the MGCF in the IMS network converts the call signaling into a SIP message according to the method provided by the foregoing.

 Step 607: The MGCF in the IMS network determines, according to the connection information carried in the signaling, whether a routing information corresponding to the connection information is stored, and if so, step 609 is performed; otherwise, step 608 is performed.

Since the correspondence between the connection information and the session identifier is set in the MGCF, and the correspondence between the session identifier and the routing information is set, it is carried according to the call signaling. The connection information can determine whether there is routing information corresponding to the connection information.

 Step 608: The MGCF in the IMS network performs the process according to the steps 602 - 604.

 Step 609: The MGCF in the IMS network determines, according to the routing information corresponding to the connection information, a route that passes the S-CSCF serving the called UE to the called UE, and passes the SIP message converted by the call signaling through the determined route. The S-CSCF serving the called UE, the S-CSCF serving the called UE sends the SIP message to the called UE, and the called UE processes the SIP message.

 Step 610: The calling UE of the circuit switched network initiates release signaling carrying the connection information and the E.164 number to the called UE in the IMS network.

 Step 610 and subsequent steps may also not follow step 609, but exist as a separate process.

 Step 611: After receiving the release signaling, the MGCF in the IMS network, according to the method provided by the prior art, converts the release signaling into a SIP message, that is, a BYE message.

 Step 612: The MGCF in the IMS network performs the process according to the steps 607 to 609, so that the S-CSCF serving the called UE receives the BYB message and forwards the message to the called UE.

 Step 613: The called UE removes the current call connection from the MGCF to the called UE by sending an acknowledgement message to the MGCF in the IMS network via the determined route to the S-CSCF served by the called UE.

 Step 614: The MGCF in the IMS network that receives the acknowledgment message releases the session established between the MGCF and the called UE for the call, and ends.

In step 606, after receiving the call signaling, the MGCF in the IMS network may first determine whether the SIP message converted by the call setup signaling is a session-independent SIP message, and if so, directly according to the method of the prior art. Call: The setup message is sent to the called UE; otherwise, the subsequent process of step 606 is performed. FIG. 7 is a signaling flowchart of the invention for transmitting call setup signaling from a circuit-switched network to an IMS network, where the circuit-switched network is a PSTN, and the specific steps are as follows:

 Step 700: A call setup is initiated by a calling UE of the PSTN, and the PSTN sends an IAM message to the MGCF in the IMS network.

 Step 701: The MGCF establishes a connection with the PSTN on the bearer plane by using an H.248 command.

 Step 702: The MGCF constructs a SIP INVITE message, and determines the route through the stored routing information of the current call, and sends the message to the S-CSCF that provides the service for the called UE.

 Step 703 - Step 704: The S-CSCF serving the called UE performs service control on the called UE and forwards the SIP INVITE message to the called UE by using a next hop function entity according to the route to the called UE.

 Steps 705-706: The called UE sends an Offer Response message to the S-CSCF, and the S-CSCF forwards the Offer Response message to the MGCF through the I-CSCF, where the message indicates the media stream capability of the called UE.

 Step 707: The MGCF modifies the connection parameter by using the H.248 command and instructs the MGW to reserve the resources required for the session.

 Steps 708 ~ 710, the MGCF determines the media resources required for the session that can be provided, and the MGCF follows the route to the S-CSCF and the route to the called UE, and the I-CSCF and the S-CSCF serving the called UE will Response Conf is forwarded to the called UE through the next hop function entity.

 Steps 711 ~ 713, the called UE returns a Conf Ack to the MGCF via the S-CSCF and the I-CSCF that provide services for the called UE.

 According to 714, the MGW reserves resources.

Steps 715 ~ 717. After the resource reservation is completed, the MGCF forwards the Reservation Conf to the called UE through the first-hop functional entity via the I-CSCF and the S-CSCF serving the called UE. Steps 718 ~ 720, the called UE returns the Reservation Conf to the MGCF via the S-CSCF and the I-CSCF serving the called UE.

 Steps 721 ~ 724, the called UE performs a Ringing process by the S-CSCF and the I-CSCF that provide services for the called UE.

 Step 725: The MGCF forwards the ACM message to the PSTN network.

 Steps 726 to 728: After the called UE responds, the S-CSCF and the I-CSCF that provide services for the called UE send a SIP 200 OK message to the MGCF.

 Step 729: The MGCF sends an ANM message to the PSTN.

 Step 730: The MGCF notifies the MGW to start the transmission of the media stream by using an H.248 command. Steps 731 ~ 733, the MGCF returns an acknowledgement message SIP ACK to the SIP 200 OK via the I-CSCF and the S-CSCF serving the called UE.

 FIG. 8 is a signaling flowchart of the present invention for transmitting call release signaling from a circuit-switched network to an IMS network, and the circuit-switched network is a PSTN, and the specific steps are as follows:

 Step 800: Send call release signaling to the MGCF by using the MGW.

 Step 801: The MGCF releases the connection between the PSTN and the IMS network by using an H.248 command. Step 802: The MGCF converts the call release signaling into a BYE message, determines a route by using the stored routing information of the current call, and sends the route to the S-CSCF that provides the service for the called party.

 Steps 803 to 804: After receiving the BYB message, the S-CSCF that provides the service to the called party performs service control on the called UE and forwards the message to the called UE.

 Steps 805 to 806, the called UE sends a 200 OK message to the MGCF in the IMS network via the determined route by the S-CSCF serving the called UE, and the current call connection from the called UE to the MGCF is removed.

 Step 807: The MGCF deletes the stored routing information of the current call, and sends a response to the call release signaling to the PSTN.

SIP messages when call signaling from a circuit switched network are not session related In the case of a SIP message, such as the MESSAGE of the short message conversion, it is processed according to the method described in FIG. 9. FIG. 9 is a process of transmitting a converted SIP message from a circuit switched network to an IMS network as a session-independent call signaling process. Figure, set the circuit switching network to PSTN, the specific steps are:

 Step 900: The PSTN sends signaling carrying the short message to the MGCF through the MGW.

 Steps 901 ~ 902, the MGCF converts the circuit domain short message into a SIP MESSAGE, and determines that the SIP MESSAGE is a session-independent message, so that the SIP MESSAGE is sent to the I-CSCF without using the bearer resource.

 Step 903: The I-CSCF sends a Location Query to the HSS storing the routing information of the called UE, and obtains routing information of the called UE. .

Step 904, HSS returns to I-CSCF routes called ^UE; information.

 Step 905: The I-CSCF determines the route to the called UE according to the routing information of the called UE, and further determines the route to the called UE, and sends a SIP MESSAGE message to the S-CSCF serving the called UE.

 Step 906 ~ Step 907: The S-CSCF serving the called UE performs service control on the called UE and forwards the SIP MESSAGE message to the called UE according to the route to the called UE.

 Steps 908-910: After the called UE answers, the S-CSCF and the I-CSCF that provide services for the called UE send a 200 OK message to the MGCF.

 Step 911: The MGCF sends an acknowledgement message to the PSTN.

 The second way.

In order to better implement the present invention, it is also possible to distinguish whether the SIP message converted by the call signaling from the circuit switched network is a session-independent SIP message or a session-related SIP message, as long as it is sent from the circuit switched network. The call signaling of the IMS network stores the routing information of the called UE to which the call signaling is to be sent in the MGCF of the IMS network, that is, the routing information of the called UE is stored in the storage manner of the routing information corresponding to the user identifier of the called UE. , so that The call signaling that is subsequently sent to the same called UE may be directly routed to the called UE by the S-CSCF serving the called UE according to the stored routing information of the called UE.

 The user ID of the called UE is an E.164 number identifying the called UE in the circuit switched network or a URI identifying the called UE in the IMS network, and the URI is SIP-U I or Tel-URI.

 The present invention may also associate user identities for identifying the same called UE in different networks, both establishing an E.164 number for identifying the called UE in the circuit switched network and for identifying the called UE in the IMS network. The correspondence between URIs.

 Of course, the user identifier of the called UE, such as the SIP-URI or the E.164 number corresponding to the routing information, may be used to store the routing information of the called UE, and may also identify the session identifier corresponding to the routing information, and further corresponding Connection information.

 FIG. 10 is a flow chart of a method for transmitting call signaling from a circuit switched network to a network according to the present invention, and the specific steps are as follows:

 Step 1000: During a call, the calling UE of the circuit switched network initiates call signaling carrying the E.164 number of the called UE to the called UE in the IMS network.

 Step 1001: After receiving the call signaling in the current call, the MGCF in the IMS network converts the call signaling into a SIP message according to a method in the prior art.

 Step 1002: The MGCF in the IMS network stores, according to the prior art, the route of the S-CSCF serving the called UE to the called UE as the routing information of the called UE, that is, as having a user identifier, such as SIP. The routing information of the called UE of the URI or E.164 number is stored.

 Step 1003: The MGCF in the IMS network sends the SIP message converted by the call signaling to the called UE by using the I-CSCF by using the S-CSCF serving the called UE to the called UE according to the prior art. The S-CSCF then sends the SIP message converted by the call signaling to the called UE for processing by the S-CSCF serving the called UE.

Step 1004: The calling UE of the circuit switched network initiates again to the called UE in the IMS network. Call signaling carrying the E.164 number of the called UE.

 Step 1004 and subsequent steps may also not follow step 1003, but exist as a separate process.

 Step 1005: After receiving the call signaling, the MGCF in the IMS network converts the call signaling into a SIP message according to a method provided by the prior art.

 Step 1006: The MGCF in the IMS network determines, according to the E.164 number of the called UE that is carried by the call signaling, whether the routing information corresponding to the called UE is stored. If yes, step 1008 is performed; otherwise, step 1007 is performed.

 In the present invention, the MGCF may also determine, according to the user identifier carried by the call signaling, such as a SIP-URI, whether to store routing information corresponding to the called UE having the user identifier, and if yes, perform step 1008; otherwise, perform steps 1007.

 Step 1007: The MGCF in the IMS network performs the process in steps 1001 to 1003.

 Step 1008: The routing information of the MGCF root in the IMS network corresponding to the called UE determines the route of the S-CSCF serving the called UE to the called UE, and determines the SIP message converted by the call signaling. The route is sent to the S-CSCF serving the called UE, and the S-CSCF serving the called UE sends the SIP message to the called UE for corresponding processing.

 The session-independent SIP message according to the present invention may be a SIP MESSAGE message obtained by converting a short message point-to-point protocol (SMPP) message of a circuit switched network, or may be a SIP OPTION message, a SIP IOTO message, or the like.

Since the present invention pre-sets the correspondence between the routing information corresponding to the session identifier and the connection information carried by the session identifier and the call signaling in the MGCF, when the MGCF receives the call signaling from the circuit-switched network, according to the preset route. The information acquires routing information corresponding to the connection information carried by the call signaling, so that the call signaling is routed according to the routing information to the S-CSCF serving the called UE and further routed to the called UE. Therefore, this issue The call signaling that can be sent from the circuit switched network to the IMS network, and the SIP message converted by the call signaling is a session related message, can be directly used by the MGCF to serve the called UE when the I-CSCF query is not performed. - The CSCF routes to the called UE, thereby reducing the call signaling interaction time from the circuit switched network to the IMS network, and reducing the service burden of the IMS network.

 Further, when the MGCF stores the routing information, the present invention may store the routing information corresponding to the user identifier of the called UE, so that when the MGCF receives the call signaling from the circuit switched network, the MGCF may also The preset routing information acquires routing information corresponding to the user identifier carried in the call signaling, so that the call signaling is routed to the called UE through the S-CSCF serving the called UE according to the routing information. Therefore, the present invention can transmit call signaling from the circuit switched network to the IMS network, and the SIP message converted by the call signaling can be a session-independent message or a session-related message, and can also be queried without the I-CSCF. The S-CSCF serving the called UE is directly routed to the called UE by the MGCF, thereby reducing the call signaling interaction time from the circuit switched network to the IMS network, and reducing the service burden of the IMS network.

 In order to implement the conversion of the E.164 number to the SIP-UR1, the present invention also provides a number conversion entity, which may be an MGCF or an I-CSCF, and a schematic diagram of the weight conversion entity, as shown in the figure The number conversion entity has a function module for converting an E.164 number into a SIP-URI and a module for constructing a SIP message, and when the number conversion entity receives the call carrying the E.164 number, the E.164 number carried by the call The function module sent to convert the E.164 number into a SIP-URI is converted into a SIP-URI, and then sent to the module constructing the SIP message, and the module constructing the SIP message constructs the SIP message carrying the converted SIP-URI. Forward the SIP message.

The function module for converting the E.164 number to the SIP-URI in the number conversion entity is the E UM DNS translation function module; or has the E.164 number and SIP in the function module for converting the E.164 number to the SIP-URI. - Correspondence of URI, the function module performs number conversion according to the corresponding relationship. · ' Of course, in order to realize the establishment of the call routing of the circuit switched network to the IMS network, the present invention also resets the IMS network in the prior art, that is, the E.164 number is converted to SIP in the MGCF of the IMS network. The function module of the URI, when the MGCF of the IMS network receives the call from the E.164 number of the called UE initiated by the calling UE in the circuit switched network, the number is converted into a SIP-URI by the added function module. Constructing a SIP message carrying the converted SIP-URI and transmitting the SIP message to the I-CSCF, and the I-CSCF obtains the routing information of the called UE indicated by the SIP-URI carried in the saved SIP message according to the prior art to the HSS query, according to The routing information of the called UE sends a SIP message to the called UE, and the called UE and the calling UE perform a SIP session negotiation process to complete the current call.

 The present invention can also add a function module for converting an E.164 number into a SIP-URI in the I-CSCF of the IMS network, when the MGCF of the IMS network receives the E carrying the called UE initiated by the calling UE in the circuit switched network. After the call of the .164 number is sent to the I-CSCF, the I-CSCF converts the number into a SIP-URL by the added function module to construct a SIP message carrying the converted SIP-URI, and then according to the prior art to the HSS. The query obtains the routing information of the called UE indicated by the SIP-URI carried in the saved SIP message, and sends the SIP message to the called UE according to the routing information of the called UE, and the called HE and the calling UE perform a SIP session negotiation process. Complete this call. ■ ' ■' '■ '■ . · ' '■ The function module that converts E.164 code to SIP-URI added in I-CSCF or HSS can be ENUM DNS translation function module; or has R164 number and The correspondence between SIP-URIs.

In the present invention, in order to enable the MGCF of the IMS network to route the call to the I-CSCF, a storage module storing the I-CSCF address or the I-CSCF list may also be added in the MGCF, after the MGCF receives the call of the circuit-switched network. The call can be routed to the determined I-CSCF according to the I-CSCF address stored by the own storage module or by selecting an I-CSCF from the stored I-CSCF list. P

WO 2006/099814 The above is only a preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Claims

Claim

 A method for establishing a circuit switching network to an Internet Protocol Multimedia Subsystem IMS network call route, characterized in that: in the IMS network, an E.164 number is set for a functional entity to be converted into a Uniform Resource Identifier (SIP-URI) of a session initiation protocol. The function, the method also includes:

A. The media gateway control function MGCF receives the call from the calling user equipment in the circuit switched network carrying the E.164 number indicating the called UE, and then goes to the functional entity to convert the E.164 number to The function of the SIP-URI converts the number into a SIP-URI, constructs a session initiation protocol SIP message carrying the converted SIP-URI, and sends it to the inquiry call control function I-CSCF;

 B. The I-CSCF queries the home subscriber server HSS to obtain the routing information of the called UE indicated by the SIP-URI carried in the saved SIP message, and sends the SIP message to the called UE according to the routing information of the called UE, and is called. The UE and the calling UE enter a SIP session negotiation process to complete the current call.

 2. The method of claim 1 wherein said functional entity is an MGCF or an I-CSCF.

 The method according to claim 1, wherein when the functional entity is an MGCF, the process of constructing the SIP message in step A is: filling the SIP-URI into the Request-URI field in the constructed SIP message. in.

 The method according to claim 1, wherein when the functional entity is an I-CSCF, the process of constructing the SIP message in step A is:

 The MGCF generates a SIP message carrying the telephone uniform resource identifier tel-URI formed by the E.164 number, and sends the SIP message to the I-CSCF;

 The I-CSCF replaces the tel-URI formed by the E.164 number in the SIP message with the SIP-URI.

5. The method of claim 4, wherein said generating carries E.164 number The process of the SIP message of the tel-URI formed by the code is: Filling the E.164 number into the Request-URI field in the constructed SIP message in the "tel:URT format";

 The process of replacing the tel-URI formed by the E.164 number in the SIP message with the SIP-URI is: replacing the tel-UKI in the Request-URI field in the constructed SIP message with the SIP-URI.

 The method according to claim 1, wherein the process of transmitting the SIP message to the called UE in step B is:

 The I-CSCF queries the routing information of the UE saved by the HSS according to the SIP-URI carried by the SIP message, determines the serving call control function S-CSCF that provides the service for the called UE, and learns the route to the S-CSCF, which will be constructed. Sending a SIP message to the S-CSCF;

 The S-CSCF establishes a route to the called UE according to the SIP-URI carried in the received SIP message, and sends the SIP message to the called UE.

 The method according to claim 1, wherein after the converting the E.164 number carried in the call to the SIP-URI in step A, the method further includes:

 The function entity determines that the successful overnight communication of the .164 number to the SIP-URI converts the E.164 number carried by the call into a SIP-URL. If yes, performs the subsequent steps; otherwise, returns the error carrying information. The response is to the circuit switched network, processed by the circuit switched network or the call error message is sent to the calling UE in the circuit switched network.

 8. The method according to claim 1, wherein when there is more than one HSS in the IMS network, and more than one HSS is under the jurisdiction of the subscription location server SLF, the query in step B stores the called UE subscription information. Before the HSS, the method further includes:

 After the I-CSCF queries the SLF according to the SIP-URI query SLF carried in the SIP message, and determines the HSS storing the information of the called UE with the SIP-URI, the HSS step of performing the query to store the routing information of the called UE is performed.

9. The method of claim 1 wherein 'the SIP message of step A The process of sending to the I-CSCF is:

 The I-CSCF address is set in advance in the MGCF, and the MGCF sends the SIP message to the I-CSCF corresponding to the address according to the set I-CSCF address;

 Alternatively, an I-CSCF list is set in advance in the MGCF, and the MGCF selects an I-CSCF from the I-CSCF list according to the set rule, and sends a SIP message to the selected I-CSCF.

 10. The method according to claim 1, wherein the function of converting the E.164 number into a SIP-URI is an ENUM DNS translation function;

 Or, in order to set the correspondence between the E.164 number and the SIP-URI, the E.164 number is converted into a SIP-URI according to the correspondence.

 The method according to claim 1, wherein the MGCF is an MGCF to which the called UE belongs to the IMS network.

 The method of claim 1, wherein when the MGCF is not the MGCF of the IMS network of the called UE, the process of the MGCF sending the SIP message to the I-CSCF by the step A is:

 The MGCF and the called UE's topology hidden interworking gateway I-CSCF (TfflG) in the home IMS network perform signaling interaction, obtain an I-CSCF that performs a query function, and then send the SIP message to the obtained I-I that performs the query function. CSCF.

 The method of claim 12, wherein the I-CSCF (THIG) and the I-CSCF performing the query function are the same I-CSCF.

 The method of claim 1, wherein the routing information is set in the MGCF, the method further comprising:

The MGCF receives the call signaling sent by the calling party in the circuit-switched network, and converts the call signaling into a SIP message, and then sends the converted SIP message to the called UE according to the routing information set by the MGCF.

The method according to claim 14, wherein the routing information is set corresponding to the session identifier;

 The MGCF also sets a correspondence between the session identifier and the connection information carried by the call signaling from the circuit switched network;

 The call signaling from the circuit-switched network carries the connection information of the circuit-switched link; the process of transmitting the converted SIP message to the called UE according to the set routing information is: The MGCF determines the call according to the set correspondence relationship The connection information carried by the signaling corresponds to the session identifier, and the routing information is determined according to the session identifier, and the converted SIP message is sent to the called UE according to the determined routing information.

 The method according to claim 14, wherein the routing information is routing information from the MGCF to the called UE by the serving call control function S-CSCF serving the called UE.

 17. The method according to claim 14, wherein the process of setting routing information in the MGCF is:

 Setting a correspondence between a telephone uniform resource identifier tel-URI formed by an E.164 number of the UE and a uniform resource identifier SIP-URI for the session initiation protocol of the UE in the HSS of the IMS network;

 The MGCF in the home IMS network of the called UE receives the call signaling from the E.164 number of the called UE initiated by the calling UE in the circuit switched network, and constructs a tel consisting of the E.164 number carrying the called UE. - the session initiation protocol SIP message of the URI is sent to the inquiry call control function I-CSCF;

The I-CSCF queries the correspondence between the HSS settings, and obtains the SIP-URI corresponding to the tel-URI formed by the E.164 number of the called UE in the SIP message, and obtains the routing information of the called UE according to the routing information of the UE saved by the HSS. The routing information is carried in the response message returned to the MGCF, and the routing information is stored by the MGCF.

18. The method according to claim 14, wherein the process of setting routing information in the MGCF is:

 The MGCF is configured to convert the E.164 number into a SIP-URI in the IMS network; the MGCF receives the call signaling from the calling UE in the circuit switched network carrying the E.164 number indicating the called UE, The function of converting the E.164 number into a SIP-URI converts the E.164 number carried by the call signaling into a SIP-URI, and the construct carries the converted

SIP-URI SIP message is sent to the I-CSCF;

 The I-CSCF queries the routing information of the UE saved by the HSS, and is carried by the SIP message.

The routing information of the called UE of the SIP-URI carries the routing information in the response message returned to the MGCF, and the routing information is stored by the MGCF.

 The method according to claim 14, wherein before the sending the converted SIP message to the called UE according to the routing information set by the MGCF, the method further includes:

The MGCF determines that the SIP message converted by the call signaling is not a session-independent SIP message, and performs a step of transmitting the converted SIP message to the called UE according to the routing information set in the MGCF.

 The method of claim 14, wherein before the sending the converted SIP message to the called UE according to the routing information set by the MGCF, the method further includes:

The MGCF determines the routing information corresponding to the SIP message to which the call signaling is set, and performs the step of transmitting the converted SIP message to the called UE according to the routing information set in the MGCF.

 The method according to claim 14, wherein the routing information is set corresponding to a user identifier of the called UE;

The call signaling from the circuit-switched network carries the user identifier of the called UE; the process of transmitting the converted SIP message to the called UE according to the set routing information is: the called UE carried by the MGCF according to the call signaling User ID determines that the called party is saved The routing information of the UE sends the converted SIP message to the called UE according to the determined routing information.

 22. The method according to claim 21, wherein the user identifier of the called UE is an E.164 number identifying the called UE in the circuit switched network or a URI of the called UE in the IMS network, the URI For SIP-URI or Tel-URL

 The method according to claim 22, wherein the E.164 number for identifying the called UE in the circuit switching network and the URI for identifying the called UE in the IMS network are in one-to-one correspondence.

 24. A number conversion entity, characterized in that the entity comprises a function module for converting an E.164 number into a SIP-URI and a module for constructing a SIP message, the number conversion entity will receive the E.164 number carried by the call. The function module for converting the E.164 number into the SIP-URI is converted into a SIP-URI and sent to the module constructing the SIP message. After the module constructing the SIP message carries the SIP message of the converted SIP-URI, Send the SIP message.

 25. The entity of claim 24, wherein the entity is an MGCF or an I-CSCF.

 The entity according to claim 24, wherein the function module for converting the E.164 number into the SIP-URI is an E UM DNS translation function module or has a correspondence relationship between the E.164 number and the SIP-URI. .