WO2009152767A1

WO2009152767A1 - Call establishing method and device thereof

Info

Publication number: WO2009152767A1
Application number: PCT/CN2009/072315
Authority: WO
Inventors: 金辉; 龙水平
Original assignee: 华为技术有限公司
Priority date: 2008-06-20
Filing date: 2009-06-17
Publication date: 2009-12-23
Also published as: CN101610503A

Abstract

A call establishing method includes receiving an IP Multimedia Sub-system IMS service request message with the calling user equipment identifier; obtaining the user equipment identifier and querying whether a session exists with the calling user equipment according to the user equipment identifier; using the circuit switching bearer of the existing session to establish the session if there is already a session with the calling user equipment; otherwise, establishing the circuit switching bearer. An application server is also provided, which includes a receiving unit for receiving the IMS service request message and obtaining the calling user equipment identifier; a determining unit for determining whether a circuit service bearer exists with the calling user equipment; a processing unit for processing the IMS service request message according to the determination result. The application of the present invention can distinguish the user equipment transmitting the call request according to the user identity information and the equipment identifier, and determine the pattern of establishing the session and bearer between the calling party and the called party according to the existence condition of the circuit service bearer of the user equipment.

Description

Method and device for establishing call This application is submitted to the Chinese Patent Office on June 20 and November 7, 2008, respectively, and the application numbers are 200810126968.3, 200810176510.9, and the invention names are all "a call establishment method and device". Priority of the Chinese Patent Application, the entire contents of which is incorporated herein by reference. Technical field

The present invention relates to the field of communications technologies, and in particular, to a call setup method, apparatus, and system. Background technique

At present, mobile communication networks are mainly circuit-switched (CS, Circuit-Switched), including GSM, CDMA, and the like. Each operator has established a relatively complete and rich service platform based on the CS network. The Mobile Switching Centre (MSC) is responsible for call routing and business logic execution, such as forwarding services.

The IP Multimedia Subsystem (IMS) is an IP-switched service network. The IMS supports the UE through various packet-switched access networks (currently mainly IP-capable access networks IP-CAN, IP-Connectivity Access Network). For example, GPRS) access network for IMS multimedia service, that is, IMS is a service platform based on IP-CAN, which basically corresponds to the MSC of the CS network. Compared to CS networks, IP-CAN provides higher bandwidth and supports richer services. The core of IMS is the Call Server Control Function (CSCF) entity and various application servers (AS, Application Server), where the service-call server control function (S-CSCF, Serving-CSCF) is responsible for meeting the conditions. , routing the call request to the correct AS, and the business logic is executed by the AS.

The IMS network is complex. The full deployment of the IMS network cannot be completed in a short period of time. Therefore, the CS network and the IMS network will coexist in a certain period of time. Then, the simultaneous operation of the CS and IMS service platforms will increase the operating cost. If a new service is to be introduced, the operator needs to rebuild both CS and IMS service platforms, increasing construction costs. It is a more reasonable way to transfer the functions of the CS network service platform to the IMS network and realize the unification of the service platform to reduce the new service construction cost and operation cost. The services supported by the unified service platform are called IMS Centralized Service (ICS). The UE establishes an IMS call by using the CS network to carry the voice media, and the CS bearer implements the ICS by establishing a CS call between the UE and the newly introduced service set and the Service Continuity Application Server (SCC AS). , weaken or remove the business processing logic in the MSC.

A call setup process is provided in the prior art. As shown in FIG. 1, the UE initiates a session request process through a Gm interface, which specifically includes:

The ICS UE A initiates an IMS service request to the UE B through the Gm interface, and the SDP of the request message includes the indication information that uses the CS as the bearer, and the Invite message carries the public identity information of the UE A, and the message passes the UE-A S. -CSCF forwards to SCC AS; (S101, S102)

SCC AS allocates SCC AS public service identity directory number (PSI DN, Public) for UE-A

Service Identity Directory Number ) , the role of this number is to route CS initiated calls to SCC AS; (S103)

The SCC AS sends a response message carrying the SCC AS public service identity directory number PSI DN to the UE-A through the S-CSCF; (S104, S105)

UE-A initiates a CS call request to the MSC Server with the SCC AS PSI DN as the called number;

( S106 )

The MSC Server returns a call processing message; and sends an IAM message to the MGCF according to the SCC AS PSI DN; (S107, S108)

The MGCF converts the IAM message into a SIP Invite message, and the SIP Invite message is

The S-CSCF sends the information to the SCC AS, and the SDP information of the message includes the media information of the MGW; (S109, S110)

As the B2BUA, the SCC AS associates the Invite message (session control signaling) in step S102 with the Invite message (bearer control signaling) in step S110, and merges the SDP messages in the two Invite messages into one Invite message. The message is forwarded to the UE-B via the S-CSCF; (Sill, S112) completes the process of establishing the session control signaling and the CS bearer. (S113)

It can be seen from the above scheme that the SCC AS associates the session mainly according to the public user identity information, so that when one user has two devices UE-1 and UE-2 with the same public user identity, and UE-1 has one CS session, the UE -2 In the case where there is no CS session, when UE1 initiates a second session request, the SCC AS cannot judge that the call is from the public user identity only. UE-1 is also UE-2. Therefore, it cannot be determined whether it is necessary to establish a new CS bearer for UE-1 or share an existing CS bearer, resulting in poor communication. Summary of the invention

In view of this, an embodiment of the present invention provides a call setup method and apparatus. In a system in which a circuit domain CS network and an IMS network coexist, when there are multiple user equipments having the same public user identity, the call request can be distinguished. The user equipment determines whether it is necessary to establish a corresponding bearer for the user equipment or share an existing circuit domain bearer to successfully establish a communication link.

An embodiment of the present invention provides a call setup method, including:

Receiving an IMS service request message carrying an IP multimedia subsystem, where the IMS service request message carries a calling user equipment identifier;

Obtaining the calling user equipment identifier, and querying, according to the user equipment identifier, whether the calling user equipment has a session;

If the calling user equipment already has a session, the circuit switching bearer of the existing session establishes a session.

An application server provided by an embodiment of the present invention includes:

a receiving unit, configured to receive an IMS service request message from the calling user equipment, to obtain the calling user equipment identifier;

The determining unit is configured to determine whether the calling user equipment has a circuit service bearer, and the processing unit performs processing on the IMS service request message received by the receiving unit according to the judgment result of the determining unit.

An embodiment of the present invention provides a user equipment, including:

a sending unit, configured to send a session request message that carries the identifier of the user equipment;

a storage unit, configured to store the user equipment identifier.

A method for establishing a call provided by an embodiment of the present invention includes:

Sending an IMS service request message carrying the identifier of the user equipment;

If a circuit switched bearer already exists, establishing a session and a bearer with the peer end;

If there is no circuit switched bearer, the session and bearer between the peer and the peer are established through the circuit domain session bearer. In summary, in the technical solution provided by the embodiment of the present invention, when the user equipment initiates a new session request or a session transfer request, the IP multimedia subsystem IMS service request message sent by the calling user equipment to the called user equipment carries the calling party. The identity information and the user equipment identifier are associated with the calling user equipment according to the user equipment identifier, and the session establishment process is completed. The user equipment that sends the call request can be distinguished according to the identity information and the user equipment identifier, and the manner of establishing the session and the bearer between the calling party and the called party is determined according to the situation that the user equipment has a circuit service bearer, so as to successfully establish a communication chain. road. DRAWINGS

FIG. 1 is a schematic flowchart of establishing a call by an ICS UE in the prior art;

2 is a flowchart of a call setup method provided in an embodiment of the present invention;

3 is a flowchart of a call request initiated by a Gm interface according to Embodiment 1 of the present invention; FIG. 4 is a flowchart of a call request initiated by an II interface according to Embodiment 2 of the present invention; FIG. 5 is a Gm interface according to Embodiment 3 of the present invention; A flowchart of initiating call forwarding; FIG. 6 is a schematic structural diagram of an application server provided in an embodiment of the present invention;

FIG. 7 is a schematic structural diagram of a user equipment provided in an embodiment of the present invention. detailed description

The embodiment of the present invention provides a method for establishing a call. In a system in which a CS network and an IMS network coexist, when there are multiple user equipments of the same public user identity (such as the same user), it is possible to distinguish which user equipment the call request comes from, thereby It is determined whether a new CS bearer needs to be established for the user equipment or an existing CS bearer is shared.

The IMS centralized control service ICS is supported by the transfer of the functions of the CS network service platform to the IMS network and the integration of the service platform. The user equipment UE establishes an IMS call by using the CS network to carry the voice media. The CS bearer implements the ICS by establishing a CS call between the UE and the newly introduced service set and the session continuity application server SCC AS, and at the same time, weakens or removes the MSC in the MSC. Business processing logic.

The SCC AS completes the adaptation between the CS domain signaling and the IMS domain SIP signaling, and acts as a user agent to establish and control the IMS session within the IMS domain instead of the user. Between the UE and the SCC AS, the control message for the session is transmitted through a signaling channel other than the CS call. In different access network environments, different messaging protocols may be used, and only the CS domain is connected. In time, the circuit can be transmitted through a circuit-switched service control signaling channel (eg, II interface) between the UE and the SCC; for example, when the UE is in an IP-CAN connection without VoIP capability, it can pass through the IP-CAN. The packet exchange service control signaling channel (for example, the Gm interface) between the UE and the SCC is transmitted, and the Gm interface mainly transmits the procedures related to registration, user service control, and authentication between the user and the CSCF. The Gm interface has the advantages of a large amount of transmission information and a rich transmission content with respect to the circuit-switched session control signaling channel (for example, the II interface). It is recommended that when the packet-switched service control signaling channel and the circuit-switched service control signaling channel are simultaneously available, The packet switched service control signaling channel is preferentially selected as the channel for session control message transmission.

For example, when the UE has a Gm or II interface, multiple calls can be initiated on the CS network, and the calls share the same CS bearer, that is, only the first CS call needs to establish a CS bearer, and when a second CS call request is initiated. When the CS bearer is not required to be established, the CS bearer is shared with the first CS call.

Referring to FIG. 2, an embodiment of the present invention provides a call setup method. In this embodiment, a Gm interface and an II interface are respectively used as a packet switched session control signaling channel and a circuit switched session control signaling channel, and the method includes the following steps. :

5201, the calling user equipment sends an IMS service request message to the called user equipment, where the message carries the identity information of the calling party and the user equipment identifier.

The device identifier is a unique identifier that is set in advance for different user devices of the same user; or the device identifier is a unique identifier that is assigned to different user devices of the same user during the registration process, such as GRUU; or

The device identifier is the mobile communication international identification code IMEI of the user equipment, or the mobile station international ISDN number MSISDN/mobile subscriber directory number MDN.

Typically, the device identification is stored in the user equipment.

5202, the user equipment identifier is obtained from the service request message, and it is determined whether the user equipment has a circuit service bearer; if there is a circuit service bearer, step S203 is performed, otherwise, step S204 is performed;

Through the association, it can be judged whether there is a session, and if there is a session, it is further determined whether the established circuit domain bearer.

5203. Forward the service request message to the called party, and establish a session between the calling party and the called party. And carrying

And if the calling user equipment supports the Gm interface, and sends the IMS service request message by using the Gm interface, forwarding the service request message to the called user equipment;

If the calling user equipment supports the II interface, and sends the IMS service request message through the II interface, the information obtained from the II interface generates a new service request message, and forwards the new service request message to the called user. device.

S204. Assign a public service identity directory number (PSI DN) to the calling user equipment, and send the PSI DN number to the calling user equipment, and establish a session and a bearer between the calling party and the called party by using the circuit domain CS network bearer. The PSI DN is used as the called number when the calling party initiates a circuit domain call request.

If the calling user equipment supports the Gm interface, and the IMS service request message is sent through the Gm interface, after the PSI DN number is assigned to the calling user equipment, the response message is sent to the calling user equipment, where the response message carries The PSI DN number.

If the calling user equipment supports the Gm interface, and the IMS service request message is sent through the Gm interface, the session and the bearer between the calling party and the called party are established through the circuit domain CS network bearer, including:

Initiating a circuit domain call request with the PSI DN as the called number, interacting with the MSC server, and converting the IAM message sent by the mobile switching center MSC server according to the PSI DN into an initial session protocol SIP service request message carrying the bearer control signaling;

The service request message carrying the session control signaling is associated with the SIP service request message, and the session description protocol (SDP) message in the two messages is combined and sent to the second user equipment.

Establish session control signaling and circuit domain bearer between the calling party and the called party.

If the calling user equipment supports the II interface, and the IMS service request message is sent through the II interface, the allocated PSI DN number is sent to the calling user equipment through the II interface.

According to the requirements of session continuity (ISC, IMS Server Continuity), the access network can be changed without interrupting the session when the user moves. When a user has multiple media in a session, the access network needs to be changed, and the media in the session is continuously switched. The SCC AS performs the switching function of the call branches between different access networks. When it is connected

When the ISC user equipment detects that the surrounding wireless environment changes or other changes occur, it will switch according to the previously defined switching policy. The ISC user equipment initiates a handover request from the access network to be switched to the SCC AS, and the SCC AS establishes a connection with the ISC user equipment in the handover access network, and switches the remote session connection to the new connection, and releases the cut-out connection. A session connection to the network.

In view of this, the embodiment of the present invention further provides a call forwarding method, in which an IMP service session exists between a first user equipment and a second user equipment in a PS network, and the method includes:

And receiving, by the first user equipment, a service request message with a session transfer identifier (STI) as the called number, where the session description protocol SDP field of the service request message includes the use of the circuit domain as the bearer indication information, where the service The request message carries the identity information and the device identifier of the first user equipment;

The session transfer identifier STI is an identifier used to indicate that a session transfer needs to be initiated, and may be dynamically allocated by the SCC AS or pre-stored in the UE. When the user wants to switch, the STI initiates the call with the STI as the called number. The SCC AS can determine that the call is a session transfer request according to the called number, and transfer the session control path and the media transmission path to the new network through the session negotiation.

Obtaining the first user equipment identifier, and determining whether the first user equipment has a circuit service bearer;

If the circuit service bearer does not exist, assign the PSI DN number to the first user equipment, and send the PSI DN number to the first user equipment;

Initiating a circuit domain call request with the PSI DN as the called number, and interacting with the MSC server;

The interacting with the MSC server includes:

Initiating a CS call request with the PSI DN as the called number, and transmitting the message circuit domain call request to the MSC server;

The MSC server returns a call processing message.

Converting the IAM message sent by the MSC server according to the PSI DN into an initial session protocol SIP service request message carrying bearer control signaling;

The service request message carrying the session control signaling is associated with the SIP service request message, and the SDP messages in the two messages are combined and sent to the second user equipment; Establishing session control signaling and circuit domain bearer between the first user equipment and the second user equipment.

In order to make the principles, features and advantages of the present invention more apparent, the invention will be described in conjunction with the embodiments.

Embodiment 1

In this embodiment, it is assumed that the user equipment UE-A has a session with the UE-B, the session is established through the process shown in FIG. 1, and the calling user equipment UE-A supports the Gm interface, and the UE-A passes The Gm interface sends the service request message. A call setup method provided in the embodiment of the present invention, referring to FIG. 3, includes the following steps:

S301, the calling ICS UE A initiates a session request to the called UE C through the Gm interface, and carries the public identity information and the user equipment identifier of the UE A in the service request Invite message;

The user equipment identifier is a device identifier assigned by the network, and the device identifier is assigned by different UEs of the same identity during the registration process, such as GRUU; or may be a unique identifier defined by the user, and the user defines different names for different UEs or No.; or the user equipment identifier adopts IMEI, International Mobile Equipment Identity number, or MSISDN/MDN.

Generally, the user equipment identifier is stored in the user equipment UE, and when the Invite request is initiated by the UE, it is carried in the contact information or in the SDP information.

Carryed by the contact header, as follows:

Contact=<IMEI or ^181801^/^101^>; isUEID

Or contact=<sip:[5555:: l :2:3:4]>, that is, the contact header contains a UE A IP address. Or contact=<sip:caller@example.com;gr=hdg7777ad7aflzig8sf7>, the contact header contains a UE A's GRUU.

Carryed by SDP, as follows:

a=UEID: <IMEI number or ^181801^/^101^>

Or the UE A includes the PSI DN in the SDP part of the Invite. For example, the SDP includes c, c=PSTN E164 +15551234, where 15551234 is the PSI DN, which is currently saved by UE A, or includes c= in the SDP. PSTN E164 +15559876, where 15559876 is the MSISDN/MDN number. The Invite message first arrives at the S-CSCF of UE-A;

S302: The S-CSCF forwards the Invite message to the SCC AS.

After receiving the Invite message, the SCC AS extracts the user equipment identifier, which may be an IMEI, or an MSISDN/MDN, or an IP address, or a GRUU, or a PSI DN, and queries whether the user equipment UE-A has a CS bearer:

If the UE-A does not have a CS bearer, the UE-A is assigned an SCC AS PSI DN number, and the session and the bearer between the calling and the called are established through the circuit domain CS network bearer, and the PSI DN is used as the calling originating circuit domain. The called number at the time of the call request, the specific process is to perform the steps S103 to S113 in FIG. 1 and end; if a CS bearer already exists in the UE-A, the new SCC AS PSI DN number is not allocated, and the subsequent operations are directly performed.

Since there is already a session between UE-A and UE-B, there is already a CS bearer in UE-A. Then performing the subsequent step S304;

S304: The SCC AS sends an Invite message to the UE-C, where the SDP information in the invite message sent by the UE A and the SDP information in the CS are sent, and the Invite message first arrives at the S-CSCF.

S305. The S-CSCF sends the Invite message to the UE-C.

5306. Complete UE-A and UE-C session establishment.

Preferably, the method further comprises the following steps:

(Optional) Prior to step S306, UEs A and B stop communicating via the CS bearer.

5307, (Optional) Connect UE B to a media device, such as MRFP.

In this embodiment, the public identity information of the calling user equipment and the user equipment identifier in the session request Invite message can distinguish which UE the call request comes from, thereby determining to establish a session and bearer for the corresponding user equipment.

Embodiment 2

In this embodiment, it is assumed that the user equipment UE-A has a session with the UE-B, the session is established through the process shown in FIG. 1, and the calling user equipment UE-A supports the II interface, and the UE-A passes the II. The interface sends the service request message. A call setup method provided in the embodiment of the present invention, referring to FIG. 4, includes the following steps:

S401, the ICS UE A initiates a session request to the UE C through the II interface, and carries the public identity information of the UE A in the message, and carries the user equipment identifier in the Invite message; The user equipment identifier is a device identifier assigned by the network, and the device identifier is assigned by different UEs of the same identity during the registration process, such as GRUU; or may be a unique identifier defined by the user, and the user defines different names for different UEs or No.; or the user equipment identifier adopts the mobile communication international identification code IMEI, or MSISDN/MDN.

Generally, the user equipment identifier is stored in the UE, and when the request is initiated through the II interface, it is carried in

II message.

S402, after receiving the II message, the SCC AS extracts the user equipment identifier, which may be an IMEI, or an MSISDN/MDN, or an IP address, or a GRUU, or a PSI DN, and determines whether the user equipment UE A has a CS bearer;

If the UE A does not, the UE-A is assigned an SCC AS PSI DN number, and is sent to the UE-A through the II interface;

If there is already a CS bearer in UE A, the UE-A is not assigned a new SCC AS PSI DN number and performs subsequent operations.

In this embodiment, a CS bearer already exists in the UE-A, and therefore, a subsequent step S403 is performed;

S403, the SCC AS generates an invite message according to the information obtained from the II interface and the SDP information carried by the CS, and sends the Invite message to the UE-C, where the message first arrives at the S-CSCF;

S404: The S-CSCF sends the Invite message to the UE-C.

5405. Complete UE-A and UE-C session establishment.

Preferably, the method further comprises the following steps:

(Optional) Before step S305, UEs A and B stop communicating via the CS bearer.

S307, (Optional) Connect UE B to a media device, such as MRFP.

Embodiment 3

In this embodiment, a session transfer request is initiated through the Gm interface. It is assumed that UE-A and UE-B have a VoIP session in the PS2 network, and the bearer process of the session is as shown in FIG. 1. The Gm interface of the CS network is in the PS1 network. When the user moves outside the coverage of the packet domain network PS2, the user equipment transfers the session to the CS network.

S501, the ICS UE A initiates a service request by using the STI as the called number through the Gm interface, and the SDP of the request Invite message includes the indication information that uses the CS as the bearer, and carries the public identity information of the UE A in the Invite message, and simultaneously in the Invite The message carries the user equipment identifier; The user equipment identifier is a device identifier assigned by the network, and the device identifier is assigned by different UEs of the same identity during the registration process; or may be a unique identifier defined by the user, and the user defines different names or numbers for different UEs; or The user equipment identity uses the mobile communication international identification code IMEI, or MSISDN/MDN.

Carryed by the contact header, as follows:

Contact=<IMEI or ^181801^/^101^>; is UEID

Or contact=<sip:[5555:: l :2:3:4]>, that is, the contact header contains a UE A IP address. Or contact=<sip:caller@example.com;gr=hdg7777ad7aflzig8sf7>,

That is, the contact header contains a UE A's GRUU.

Carryed by SDP, as follows:

a=UEID: <IMEI number or ^181801^/^101^>

Or UE A includes a PSI DN in the SDP part of Invite, such as including c lines in the SDP.

c=PSTN E164 +15551234, where 15551234 is the PSI DN is currently saved by UE A, or c=PSTN E164 +15559876 is included in the SDP, where 15559876 is

MSISDN/MDN number.

The message first arrives at the S-CSCF of UE-A;

S502, the S-CSCF of the UE-A forwards the message to the SCC AS.

S503: After receiving the Invite message, the SCC AS extracts the user equipment identifier, which may be an IMEI, or an MSISDN/MDN, or an IP address, or a GRUU, or a PSI DN, and determines whether the user equipment has a CS bearer.

If there is no CS bearer, the UE-A is assigned the SCC AS PSI DN number; if there is already a CS call, the SCC AS PSI DN is not allocated to the user, and the SCC AS sends an Invite message to the UE-C, which includes the UE A. The SDP information in the sent invite message and the SDP information carried by the CS, the message first arrives at the S-CSCF. It is assumed here that the UE-A does not currently have a CS bearer, so the UE-A is assigned an SCC AS PSI DN number;

S504, the SCC AS sends the SCC AS PSI DN to the UE-A by using a response message, where the message first arrives at the S-CSCF; S505: The S-CSCF sends a response message including the SCC AS PSI DN number to the UE A.

5506, UE-Α initiates a CS call request with the SCC AS PSI DN as the called number, and the message first arrives at the MSC Server;

5507, the MSC Server returns a call processing message;

S508. The MSC server sends an IAM message to the MGCF according to the SCC AS PSI DN.

5509. The MGCF converts the IAM message into a SIP Invite message, and sends the SIP Invite message to the S-CSCF, where the SDP information of the message includes the media information of the MGW.

5510, the S-CSCF sends the message to the SCC AS;

5511, the SCC AS acts as a back-to-back user agent (B2BUA), and the B2BUA is a logical entity for processing the request, and associates the Invite message (session control signaling) in step S502 with the step S510. Invite message (bearer control signaling), and merges the SDP messages in the two Invite messages into one re-Invite message, and the message is forwarded to the UE-B via the S-CSCF, and the message is used to update the peer end, and Media transfer path update.

5512, the S-CSCF sends the message to the UE-B.

S513. Complete session control signaling and establishment of a CS bearer.

An embodiment of the present invention further provides an application server. As shown in FIG. 6, the application server 600 includes:

The receiving unit 610 is configured to receive an IMS service request message from the calling user equipment, and obtain the calling user equipment identifier.

The determining unit 620 is configured to determine whether the calling user equipment has a circuit service bearer; the processing unit 630, according to the determining result of the determining unit 620, performing an IMS service request message received by the receiving unit 610 for processing;

An allocating unit 640, configured to allocate a PSI DN number to the calling user equipment;

The sending unit 650, the PSI DN number and the service request message allocated by the allocating unit S640 are sent;

When the determining unit 620 determines that the calling user equipment does not have a circuit service bearer, the allocating unit 640 allocates a PSI DN number to the calling party user equipment;

When the determining unit 620 determines that the calling user equipment has a circuit service bearer, the service request message is forwarded to the called user equipment. The device identifier is a unique identifier that is set in advance for different user devices of the same user; or the device identifier is a unique identifier that is assigned to different user devices of the same user during the registration process; or

The device identifier is a mobile communication international identification code IMEI of the user equipment.

The embodiment of the present invention further provides a call setup system, including a service call session control function entity S-CSCF and an application server;

The application server 600 is configured to receive a session request message from the calling user equipment, obtain the calling user equipment identifier, and determine whether the user equipment has a circuit service bearer; when determining that the user equipment does not have a circuit service The bearer, the PSI DN number is assigned to the calling user equipment; the PSI DN number is sent to the calling user equipment; when the user equipment has a circuit service bearer, the service request message is forwarded to the called party;

The S-CSCF is configured to forward the message sent by the application server to the called user equipment, and establish a session and a bearer between the calling user equipment and the called user equipment.

If the calling user equipment supports the Gm interface, and the session request message is sent through the Gm interface, the serving call session control function entity S-CSCF forwards the service request of the autonomous call to the application server.

The embodiment of the present invention further provides a user equipment 700, as shown in FIG. 7, including:

The sending unit 710 is configured to send a session request message that carries the user equipment identifier.

The storage unit 720 is configured to store the user equipment identifier.

The receiving unit 730 is configured to receive the allocated PSI DN number.

The session establishing unit 740 initiates a circuit domain call request with the PSI DN as the called number, and establishes a session.

The user equipment identity may be transmitted over a packet switched network traffic control signaling channel or a circuit switched network traffic control signaling channel.

If the packet is sent by using the packet-switched network service control signaling channel, and the sending unit 710 sends a session request message carrying the user equipment identifier, the user equipment identifier is carried in the contact information or in the SDP information for transmission.

In summary, in the technical solution provided by the embodiment of the present invention, when the user equipment initiates a new session request or a session transfer request, the request message sent by the calling user equipment to the called user equipment is carried. The identity information of the calling party and the user equipment identity are forwarded to the called party, and the session between the calling party and the called party is established, and the user that can distinguish the sending call request according to the identity information and the user equipment identity is established. The device determines the manner of establishing a session and a bearer between the calling party and the called party according to the situation that the user equipment exists in the circuit service bearer.

It will be apparent to those skilled in the art that the various units or steps of the present invention described above can be implemented by a general-purpose computing device that can be centralized on a single computing device or distributed across a network of multiple computing devices. Alternatively, they may be implemented by program code executable by the computing device, such that they may be stored in the storage device by the computing device, or they may be separately fabricated into individual integrated circuit modules, or they may be Multiple units or steps are made in a single integrated circuit module. Thus, the invention is not limited to any specific combination of hardware and software.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention. Any modifications, equivalents, improvements, etc. made within the spirit and scope of the invention are intended to be included within the scope of the invention.

Claims

Rights request

A call setup method, characterized in that it comprises:

Receiving an IP multimedia subsystem IMS service request message, where the IMS service request message carries a calling user equipment identifier;

2. The call setup method of claim 1, further comprising: establishing a circuit switched bearer between the calling party and the called party if the calling user equipment has a session.

The call setup method according to claim 1 or 2, wherein the caller device identifier is carried in the contact contact information or in the session description protocol SDP information, and the user equipment identifier is obtained. Includes:

Extracting the user equipment identifier from the contact information or the SDP information.

The method for establishing a call according to claim 2, wherein the establishing a circuit switched bearer between the calling party and the called party comprises:

Allocating a public service identity directory number PSI DN number to the calling user equipment, and sending the PSI DN number to the calling user equipment;

The PSI DN is used as the called number when the calling party initiates the circuit domain call request, and the circuit domain call is used to establish a circuit switched bearer, and the session between the calling party and the called party is established through the circuit domain session bearer.

5. The call establishing method according to claim 1 or 2, characterized in that

The device identifier is a mobile communication international identification code IMEI, or a mobile station international ISDN number MSISDN, or a mobile subscriber directory number MDN, or an IP address, or a GRUU, or a public service identity directory number PSI DN.

The call setup method according to claim 1 or 2, wherein the device identification is stored in the user equipment.

7. The call establishing method according to claim 1 or 2, characterized in that

The calling user equipment identity is communicated through a packet switched network service control signaling channel or circuit The network service control signaling channel is changed for transmission.

8. The call setup method according to claim 7, wherein if the calling user equipment transmits the message by using a packet switched network service control signaling channel,

When the calling user equipment sends a session request message carrying the user equipment identifier, the user equipment identifier is included in the contact contact information or in the session description protocol SDP information for transmission.

The method for establishing a call according to claim 1 or 2, further comprising: after the IMS service session is established between the calling user equipment and the called user equipment, receiving the session transfer sent by the calling user equipment A session request message identifying the STI as the called number.

10. An application server, comprising:

The application server according to claim 10, further comprising: an allocating unit, configured to allocate a PSI DN number to the calling user equipment;

a sending unit, configured to send a PSI DN number and a service request message allocated by the allocating unit; and when the determining unit determines that the calling user equipment does not have a circuit service bearer, the allocating unit allocates a PSI to the calling user equipment DN number;

And when the determining unit determines that the calling user equipment has a circuit service bearer, forwarding the service request message to the called user equipment.

12. The application server of claim 10, wherein

The device identifier is a mobile communication international identification code IMEI of the user equipment, or a mobile station international ISDN number MSISDN/mobile subscriber directory number MDN, or an IP address, or a GRUU, or a public service identity directory number PSI DN.

13. A user equipment, comprising:

a storage unit, configured to store the user equipment identifier.

The user equipment of claim 13, further comprising: a receiving unit, configured to receive the allocated PSI DN number;

The session establishing unit initiates a circuit domain call request with the PSI DN as the called number, and establishes a session.

The user equipment according to claim 14, wherein the session request sent by the sending unit carries a contact contact message or a session description protocol SDP message.

16. A call setup method, comprising:

If there is no circuit switched bearer, the session between the peer and the peer is established through the circuit domain session bearer.

The call setup method according to claim 16, wherein the device identifier is a unique identifier set in advance for different user equipments of the same user; or

The device identifier is a unique identifier assigned to different user devices of the same user during the registration process; or

18. The call establishing method according to claim 16, wherein:

The calling user equipment identity is transmitted over a packet switched network traffic control signaling channel or a circuit switched network traffic control signaling channel.

The call setup method according to claim 18, wherein if the calling user equipment transmits the message by using a packet switched network service control signaling channel,

When the calling user equipment sends a session request message carrying the user equipment identifier, the user equipment identifier is carried in the contact information or in the SDP information for transmission.