WO2007137485A1

WO2007137485A1 - Methods and systems for implementing call transfer and home network of user terminal

Info

Publication number: WO2007137485A1
Application number: PCT/CN2007/001539
Authority: WO
Inventors: Youzhu Shi
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2006-05-26
Filing date: 2007-05-11
Publication date: 2007-12-06
Also published as: CN101080083A

Abstract

Methods and systems for implementing call transfer and home network of user terminal are disclosed. One of the methods comprises: the home network of substituted user receiving a first call transfer instruction; the home network of substituted user setting up a second call at the third user terminal to the transfer user terminal based on the first call transfer instruction, and redirecting the call at the transfer user terminal to the substituted user terminal to the third user terminal. Because the transfer user terminal is calling with the substituted user terminal, the transfer user terminal trusts in the substituted user terminal, vice versa. And the home network of the substituted user can get the dialog id in the substituted user terminal side and also get the dialog id in the transfer user terminal side, therefore the call transfer can be implemented successfully.

Description

Method and system for realizing call steering, home network of user terminal

The present application claims priority to Chinese Patent Application No. 200610035635.0, entitled "Calling Method and System for Calling", filed on May 26, 2006, the entire contents of which is incorporated herein by reference. .

Technical field

The present invention relates to the field of communications, and in particular, to a method and system for implementing call forwarding and a home network of a user terminal.

Background technique

Call steering is a common telecommunication service. Generally speaking, two users are in a call contact. After some operation, one user (turning to the user) is turned to the third party, and the other user is replaced. User) quit. The above operation is generally performed by one of the two users, but it can also be the above-mentioned third-party user. For example, the Call Pickup service is a typical application in this scenario.

The call pickup service refers to: the calling user calls the called user, and the called user's terminal rings. At this time, the third-party user can answer the call by the called party, and the third-party user and the calling user talk. The user who called the user exits the call and stops ringing. In this service, the calling user is the diverted user, and the called user is the replaced user.

Prior art one:

In the draft "raft-ietf-sipping-service-examples-10.txt" issued by the Internet Engineering Task Force (IETF), a call using SIP (Session Initiation Protocol) as call control signaling is given. The implementation process of the pickup business. Referring to Figure 1, a data flow diagram of the call pickup service given in the above draft is illustrated. As shown, the process includes the following steps:

1. The UE (user terminal) 100 calls the UE 200 to send a SIP INVITE message;

2. The UE 200 rings and sends a 180 Ringing Ringing Response Code to the UE 100. At this time, the UE 100 and The UE 200 establishes a session, and the session identifier is Dialog-1;

If the UE 200 and the ΌΕ300 have signed the call pickup service, the service contract UE300 can answer the call in place of the UE 200. In this example, the UE 100 can be referred to as a redirected user, the UE 200 as a substitute user, and the UE 300 as a third-party user.

3. The UE 300 sends a SIP SUBSCRIBE subscription message to the UE 200, requesting to subscribe to the current UE tongue information;

4. The UE 200 sends a SIP NOTIFY notification message to the UE 300, where the message includes the session identifier Dialog-1 and the remote user identifier of the session identifier (ie, the identifier of the UE 100).

Steps 3 and 4 are processes in which the UE 300 obtains the session status of the UE 200.

5. The UE 300 initiates a call to the UE 100, and sends a SIP INVITE message. The message Replaces header field carries the session identifier Dialog-1, indicating that a session is established between the UE 300 and the UE 100 to replace the session Dialog-1;

6. The call is established between UE300 and UE100, and a session is established, and the session identifier is Dialog-2;

7. The UE 100 releases according to the indication of the Replaces header field in the INVITE message sent by the UE 300.

Dialog-1 session, sending a SIP CANCEL message to UE200;

8. The session is handled between the UE 100 and the UE 200, and the UE 200 stops ringing.

In the process of implementing the present invention, the inventors found that at least the following problems exist in the above process:

1) The procedure assumes that there is only one session identifier (Dialog-1) for the call between the UE 100 and the UE 200. In fact, there may be more than one session identifier for the call between the UE 100 and the UE 200, such as at the UE 100 and the UE 200. There is a B2BUA (Back to Back User Agent) network element in the call signaling path, such that a session identifier (such as Dialog-lb) exists between the UE 100 and the B2BUA network element, and the B2BUA network element and the UE 200 There is another session identifier (such as Dialog-lc). In this case, the UE 300 subscribes to the UE 200 only the session identifier (Dialog-lc) of the UE 200, and the UE 300 carries the INVITE message sent to the UE 100. It will also be the Dialog-lc session identifier, and the session identifier of the UE 100 is Dialog-lb. Obviously, the UE 100 may determine that the session identifier carried in the Replaces header field in the received INVITE message is not at the local end, thereby rejecting the call from the UE 300. Or even if the UE 100 ignores this situation and establishes a call with the UE 300, it will not be able to revoke the call already established with the UE 200, thereby causing the call pickup service application to fail.

2) The UE 300 directly initiates a new call to the UE 100 to replace the current session of the UE 200 as a call steering control operation. Generally, the UE 300 and the UE 200 have a mutual trust relationship, but the UE 100 may be in another country as the redirecting user, and the UE 300 There is no mutual trust relationship, and UE100 may reject this call steering control operation.

Prior art 2:

Telecommunications and Internet Converged Services and Protocols for Advanced Networking (TISI) of ETSI (European Telecommunications Standards Institute) also used SIP as a recent paper in "10tTD036 New- WI-Session-Mobility_cover.doc". A third-party user of call control signaling controls an implementation flow of call forwarding. Referring to Figure 2, a schematic data flow of the implementation flow is illustrated. As shown, the process includes the following steps:

1. The UE 100 and the UE 200 have established a call contact. The AS (Application Server) 400 is used as the B2BUA network element in the signaling path of the call, and the session identifier between the AS400 and the UE 100 is Dialog-lb, and the session identifier between the UE and the UE 200. For Dialog-2;

2. The UE 300 initiates a third-party control, and sends a SIP REFER reference message to the UE 200. The Refer-To header field of the REFER message points to the UE 300, indicating that the request 200 sends another SIP REFER message to the UE 300, and the content of the latter REFER message is in the Refer. -To set in the header field, the UE 300 is required to send a SIP message to the UE 100 instead of the session corresponding to the session identifier Dialog-2. 3. The AS400 intercepts the REFER message from the UE 300 and sends a SIP REFER to the UE 300 according to the message request. Message 4. The UE 300 receives the REFER message from the AS400, and sends a SIP INVITE message to the UE 100 to replace the session corresponding to the session identifier Dialog-2 according to the message request. The message indicates that the INVITE message is from the network (AS) through the Referred-By header field. Steering control

It can be seen that the shortcoming 2 in the prior art is solved here, that is, the UE 300 sends a call steering control operation to the UE 200. As described above, there is a mutual trust relationship between the two, and the UE 200 accepts such an operation and passes The operation controls the UE 300 to initiate a new call to the UE 100 in place of the current session of the UE 100, and the steering control in the call indicating that the call is from the network is trustworthy. That is to say, the UE300's new call carries the UE 200's approval information, and the UE 100 trusts the new call according to the approval information, thereby overcoming the shortcomings in the prior art 1.

5. The AS 400 receives the INVITE message from the UE 300, and according to the B2BUA mechanism, the session identifier of the call where the Dialog-2 session identifier is located on the side of the UE 100 is Dialog-lb, according to the session description protocol of the UE 300 carried in the received INVITE message. (SDP) information, redirecting the session corresponding to the Dialog-lb session identifier to the UE300, and sending a SIP re-INVITE re-invitation message;

6. The session Dialog-lb redirection is completed, and the UE 100 is redirected from the UE-oriented connection to the UE 300 connection;

7. The call setup between the AS400 and the ΌΕ300 is completed, and the corresponding session identifier is Dialog-la. The specific process is omitted. The call connection between the UE300 and the UE100 is established, and the AS400 acts as the B2BUA network element in the call signaling path.

8. Dry session Dialog-2, AS400 sends a SEP BYE goodbye message to UE200;

9. Session Dialog-2 is released and UE 200 exits the call with UE 100.

In the process of implementing the present invention, the inventor has found that at least the following problems exist in the flow of the prior art: The flow of the prior art 2 considers that there is a B2BUA network element in the call signaling path between the UE 100 and the UE 200. However, the process still has the disadvantages similar to the disadvantage 1 of the prior art. This is because the UE 100 and the UE 200 are likely not in the same home domain network, so that the AS 400 in the above process is either in the home domain network of the UE 100 or in the home network of the UE 200. Network. As can be seen from step 3, the AS 400 intercepts the SIP REFER message sent by the UE 300 to the UE 200. Obviously, the AS 400 is located in the home domain network of the UE 200. Thus, in step 4, since the UE 300 is transmitting a SIP INVITE message to the UE 100, it is apparent that the INVITE message cannot actually reach the AS 400. The message can only reach the network element in the home network of the UE 100. The network element obviously cannot identify the Dialog-2 session identifier carried in the INVITE message, and the third-party controlled call to the service application fails. That is to say, in fact, it is impossible for the UE 100 and the UE 200 to share the AS 400 as a common B2BUA network element, and the technical solution of the prior art 2 cannot be realized in reality.

In summary, the shortcomings of the prior art are due to the establishment of two levels of conditions: First, a third party directly initiates a new call to the user; second, the new call carries a replacement. The session ID of the user's local end, which prevents the new call from being established. This is the reason for the above shortcomings. That is to say, if the first level condition is overcome, the technical problem can be solved, or the technical problem can be solved by overcoming the second level condition while preserving the first level condition.

Summary of the invention

The object of the embodiments of the present invention is to provide a method and system for implementing call forwarding, a home network of a user terminal, and a call steering technology capable of implementing a three-party control in a communication network, to solve a new call between a third party user and a steering user. Technical problem.

The first aspect provides a method for implementing call forwarding. The first call is established between the user terminal and the replaced user terminal, and includes the following steps:

Receiving, by the home network of the substitute user terminal, a first call steering instruction, where the first call steering instruction includes at least an identifier of the third-party user terminal;

The home network of the replaced user terminal establishes a second call of the third-party user terminal to the redirected user terminal according to the first call steering instruction, and faces the redirected user terminal to the replaced user terminal The established session is redirected to the third party user terminal.

In the above method for implementing call forwarding, a new call is established by the home network of the replaced user terminal, and the session established with the redirected user terminal is redirected to the third user terminal. Due to being replaced The user terminal is in a call with the redirecting user terminal, and the replaced user has a trust relationship with the redirecting user; and the home network of the replaced user terminal can obtain the session identifier of the replaced user terminal side, and can also obtain the steering user terminal side. The session ID so that the call can be successfully diverted. That is to say, the third-party user terminal does not need to directly call the user, but the substitute user acts as an intermediary to establish a new call to the user, thereby completely solving the problem of the first level condition in the prior art, and successfully establishing a new one. The call, completing the call steering controlled by the third party user, achieves the object of the present invention. The second aspect provides another method for implementing call forwarding. The first call is established between the user terminal and the replaced user terminal, and the method includes the following steps:

Receiving, by the home network of the user terminal, a first call steering instruction, where the first call steering instruction includes at least an identifier of the third-party user terminal;

And the home network that turns to the user terminal establishes a second call of the third-party user terminal to the redirected user terminal according to the first call steering instruction, and faces the redirected user terminal to the replaced user The session that the terminal has established is redirected to the third party user terminal.

In the above method for implementing call forwarding, the third-party user terminal obtains a steering by requesting the home network of the replaced user terminal as an intermediary in the call steering instruction before establishing a new call with the redirecting user terminal. The home network of the user terminal faces the session identifier on the side of the replaced user terminal, so that a new call can be successfully established with the redirected user in the subsequent new call setup process. That is to say, the method retains the existing one-level condition of the prior art, that is, the third-party user terminal directly establishes a call with the redirecting user (the third-party user terminal initiates a new call or actively transfers the third party to the home network of the user) User), overcomes the second level condition, that is, obtains the session identifier of the home network turned to the user terminal facing the replaced user terminal side, so that the new call can be successfully established, and the third party user controlled call steering is completed, and the present invention is realized. purpose.

The third aspect provides a home network of the user terminal, and the first call is established between the user terminal and the replaced user terminal, including:

a receiving unit, configured to receive a call steering instruction, where the call steering instruction includes at least a first The identity of the three-party user terminal;

a calling unit, configured to establish, according to the call steering instruction, a second call of the third-party user terminal to the redirected user terminal, and redirect the redirected user terminal to a session that has been established by the replaced user terminal To the third party user terminal.

In a fourth aspect, a system for implementing call forwarding is provided, including a redirected user, a replaced user, and a third-party user, the redirected user including a redirected user terminal, the replaced user including the replaced user terminal and the In addition to the service network element coupled to the user terminal, the third-party user includes a third-party user terminal, and the redirected user, the replaced user, and the third-party user are coupled to each other, and can communicate with each other, and switch to the user terminal and be replaced. The first call has been established between the user terminals:

The third-party user terminal is configured to send a call steering instruction to the replaced user, where the call steering instruction includes at least the replaced user identifier;

The service network element is configured to establish, according to the call steering instruction, a second call of the third-party user terminal to the redirected user terminal, and target the redirected user terminal to the replaced user terminal. The session is redirected to the third party user terminal.

The above-mentioned system for implementing call forwarding is a system for implementing the method for implementing call forwarding provided by the first aspect of the present invention, and its features and advantages are the same as those of the calling method, and are not described herein again.

A fifth aspect provides a system for implementing call forwarding, including a redirecting user, a replaced user, and a third-party user, the steering user including a steering user terminal and a first service network element coupled to the steering user terminal, The replaced user includes a replaced user terminal and a second service network element coupled to the replaced user terminal, the third party user includes a third party user terminal, the redirected user, the replaced user, and the first The three-party users are coupled to each other and can communicate with each other. The first call has been established between the user terminal and the replaced user terminal:

The third-party user terminal is configured to send a call steering instruction to the replaced user, where the call-turning instruction includes at least the identifier of the replaced user;

The second service network element is configured to send a subsequent message flow obtained according to a call forwarding instruction request Giving the first service network element or the third party user terminal;

The first service network element is configured to establish a second call of the third-party user terminal to the redirected user terminal, and redirect the redirected user terminal to a session that has been established by the replaced user terminal to Said third party user terminal.

The above-mentioned system for implementing call forwarding is a system for implementing the method for implementing call forwarding provided by the second aspect of the present invention, and its features and advantages are the same as those of the calling method, and are not described herein again. DRAWINGS

1 is a data flow diagram of a call steering method in prior art 1;

2 is a data flow diagram of a call steering method in the prior art 2;

3 is a block diagram of a system for implementing call steering in an embodiment of the present invention;

4 is a data flow diagram of a method for implementing call steering according to an embodiment of the present invention;

FIG. 5 is another data flow diagram of a method for implementing call steering according to an embodiment of the present invention; FIG. 6 is a block diagram of a system for implementing call steering according to another embodiment of the present invention;

FIG. 7 is a data flow diagram of a method for implementing call forwarding according to another embodiment of the present invention; FIG. 8 is another data flow diagram of a method for implementing call steering according to another embodiment of the present invention.

detailed description

A more detailed technical solution of the present invention will be given in detail in the following detailed description in conjunction with the accompanying drawings. Embodiment 1

Referring to Figure 3, a system for implementing call steering provided by the present invention is illustrated. As shown, the system includes a diverting user 1, an alternate user 2, and a third party user 3. It should be noted that each user in the figure is actually a user terminal home network in a communication network, and the present invention only gives the logical functional units in each home network involved in the present invention, but this is not It is meant that the environment in which the invention is implemented includes only the elements listed in the figures. The steered user 1 includes a steered user terminal (ie, UE 100), and the replaced user 2 includes a replaced user terminal (ie, UE 200) and a service network element (ie, AS 210) coupled to the UE 200, the third party user 3 Including third-party user terminals (ie The UE 300, the redirected user 1, the replaced user 2, and the third-party user 3 are coupled to each other, and can communicate with each other.

Referring to FIG. 4, a data flow based on one embodiment of a call steering method of the system for implementing call steering in FIG. 3 is illustrated. It should be noted that the flowcharts and texts in the present invention are merely illustrative of the key techniques of the present invention, and do not represent a complete call and service control process, nor do they exhaust all possible branching processes. However, one of ordinary skill in the art will be aware of all possible branching processes. As shown, a call turn includes the following steps:

1. UE 100 and UE 200 establish a call connection (which may be referred to as a first call). In the home network of the UE 200, the AS 210 is in the signaling path of the call as the B2BUA network element, the session identifier to the UE 100 side is Dialog-lb, and the session identifier to the UE 200 side is Dialog-2. This step is a prerequisite for the call steering method.

2. The UE 300 obtains the current session of the UE 200. For the specific process, reference may be made to the related description in the prior art. If the current session state of the UE 200 has more than one session, the UE 300 may select a session, which may be an artificial selection. Alternatively, the terminal may automatically select according to a certain rule, such as automatically selecting a session in a ringing state according to the chronological order. Through this step, the UE 300 can obtain the session identifier Dialog-2 on the UE 200 side.

3. The UE 300 sends a call steering command to the home network of the UE 200. The instruction carries the identifier of the session to be replaced (Dialog-2) and the call forwarding service identifier, and at least the identifier of the UE 200 is included in the call steering instruction, because only the identity of the UE 200 can be correctly arrived at the home network of the UE 200. The call forwarding service identifier indicates that the UE 300 wishes to establish a call connection with the remote user (ie, UE 100) whose session identifier is a Dialog-2 session, instead of the UE 200. Specifically, in this embodiment, the UE 300 adopts a SIP SUBSCRIBE message, and the call header service domain carries an extended event packet pickup to indicate the call forwarding service identifier, and the replace header field carries the session identifier Dialog-2 obtained in step 2.

4. The B2BUA network element AS210 in the home network of the UE 200 receives the from the UE 300. The SUBSCRIBE message, according to the call forwarding service identifier in the message, the AS 210 initiates a new call to the UE 300 (which may be referred to as a second call). Specifically, the AS 210 sends a SIP INVITE message to the UE 300, where the message carries the SDP information of the UE 100.

5. A second call is established between the UE 300 and the AS 210, and the corresponding session identifier is Dialog- la. The specific process is omitted. The AS210 can obtain the SDP information of the UE 300 at this time.

6. According to the B2BUA mechanism, the AS210 obtains the session identifier of the Dialog-2 session identifier on the UE 100 side as Dialog-lb, and redirects the session corresponding to the Dialog-lb session identifier to the UE 300 by using the SDP information of the UE 300, and sends the SIP to the UE 100. re-INVITE re-invites the message.

7. The session Dialog-lb redirection is completed, and the UE 100 is redirected from the UE-oriented connection to the UE 300 connection.

It can be seen that step 4-7 is actually a process in which the home network of the UE 200 establishes a second call with the UE 300 and redirects the session with the UE 100. The service network element AS210 (specifically, the B2BUA network element) in the home network of the UE 200 is based on the B2BUA mechanism, and after obtaining the session identifier Dialog-2 on the UE 200 side sent by the UE 300, the UE 100 side corresponding to the session can be known. The session identifier Dialog-1, and a new call can be established according to the call steering command sent by the UE 300. That is to say, the new call in the call forwarding (ie, the second call refers to the new call that the third party user wants to replace the first call where the substitute user is located) is indicated by the UE 300, and is established by the home network of the UE 200. Thereby, the trust problem between the UE 300 and the UE 100 is avoided and the disadvantage that the UE 300 does not know the session identifier of the UE 100 side and thus cannot establish a new call is overcome. This enables third party user control call steering.

8. Release session Dialog-2, AS210 sends a SIP BYE goodbye message to UE200.

9. The session Dialog-2 is released and the UE 200 exits the call with the UE 100.

As a result, a complete third-party user-controlled call turn is complete.

In the foregoing embodiment, the UE 300 adopts the SIP SUBSCRIBE message as the call steering instruction, which is only an example, and may also adopt other manners as the call steering instruction, as long as the command carries The identifier of the session to be replaced, the identity of the session to be replaced, and the call to the service identifier can be used.

It is worth noting that Step 2 is not necessary. The UE 300 may not need to know the session state of the UE 200 in advance, but select one of the session queues of the UE 200 by the home network of the UE 200. A specific embodiment is given below for this technique.

Specific embodiment 2:

Referring to Figure 5, a data flow based on another embodiment of the call steering method implementing the call steering system of Figure 3 is illustrated. As shown, a call turn includes the following steps:

1. UE 100 and UE 200 have established a call contact (which may be referred to as a first call). In the home network of the UE 200, the AS 210 is in the signaling path of the call as the B2BUA network element, the session identifier to the UE 100 side is Dialog-lb, and the session identifier to the UE 200 side is Dialog-2. This step is a prerequisite step for the call steering method.

2. The UE 300 sends a call steering instruction to the UE 200, where the command only carries the UE 200 identifier and the call forwarding service identifier. Specifically, in this embodiment, the call steering instruction is a SIP INVITE message, and the extended header packet carries an extended event packet pickup to indicate the call forwarding service identifier, and the message carries the SDP information of the UE 300 at the same time.

3. The B2BUA network element AS210 in the home network of the UE 200 determines the call connection that the current UE 200 has established. If there is more than one, according to a certain rule, such as the sequence of call establishment, the call status (ringing status, call status, etc.) Etc., choose a session to be replaced. In this example, AS210 selects the Dialog-2 session to be replaced.

4. According to the B2BUA mechanism, the AS210 obtains the session identifier of the Dialog-2 session identifier on the UE100 side as Dialog-lb, and redirects the session corresponding to the Dialog-lb session identifier to the UE300 by using the SDP information of the UE300, and sends a SIP re -INVITE re-invites the message.

5. The session Dialog-lb redirection is completed, and the UE 100 is redirected from the UE-oriented connection to the UE 300 connection. The specific process is omitted.

6. A new call (second call) is established between UE300 and AS210, and the corresponding session identifier is Dialog-la, the specific process is slightly.

It can be seen that steps 3-6 are actually a process in which the home network of the UE 200 establishes a second call with the UE 300 and redirects the session with the UE 100. Compared with the previous embodiment, this embodiment is a connection for establishing a new call after being redirected. In this embodiment, the call steering instruction of the UE 300 is actually a call setup command, but the command is not sent to the UE 100, but is sent to the UE 200. When the command is acquired by the AS 210 in the home network of the UE 200, the AS 210 According to the information provided by the instruction, a session identifier to be redirected is selected in the session queue of the UE 200, and the session identifier of the session remote end (such as the UE 100 in this example) corresponding to the session identifier is obtained according to the B2BUA mechanism, and then redirected first. Then help establish a new call connection. In this way, although the new call connection is issued by the UE 300, the establishment of the connection is established under the control of the AS 210, thereby providing the advantages described in the previous embodiment.

7. Release session Dialog-2, AS210 sends a SIP BYE goodbye message to UE200.

8. The session Dialog-2 is released and the UE 200 exits the call with the UE 100.

As a result, a complete third-party user-controlled call turn is complete.

As described above, the reason why the process of the second embodiment can be redirected to establish a new call connection is that the call forwarding instruction sent by the UE 300 carries the SDP information of the UE 300. In fact, if the call is sent by the UE 300 in the first embodiment, The command (SIP SUBSCRIBE message) carries the SDP information of the UE300, and may also be redirected to establish a new call connection.

As described above, in the process of the second embodiment, the call forwarding instruction does not carry the session identifier to be replaced, but the AS 210 selects the session from the UE 200 according to the call forwarding service identifier carried in the received call forwarding instruction. A session identifier to be replaced. In addition, if the call forwarding command carries the user identifier of the UE 100, the AS 210 can also select a session identifier to be replaced from the session situation of the UE 200, that is, select the session established by the UE 200 and the UE 100. The session ID is used as the session identifier to be replaced.

Specific embodiment 3:

Referring to Figure 6, another system for implementing call steering provided by the present invention is illustrated. as the picture shows, The system includes a diverting user 1, an alternate user 2, and a third party user 3. It should be noted that each user in the figure is actually a user terminal home network in a communication network, and the present invention only gives the logical functional units in each home network involved in the present invention, but this is not It is meant that the environment in which the invention is implemented includes only the elements listed in the figures. The redirected user 1 includes a redirected user terminal (ie, UE 100) and a first serving network element (ie, AS 110) coupled to the redirected user terminal, the replaced user 2 including the replaced user terminal (ie, UE 200) and the The second serving network element (ie, AS 210) is coupled to the UE 200, and the third-party user 3 includes a third-party user terminal (ie, the UE 300). The steering user 1, the replaced user 2, and the third party user 3 are coupled to each other, and can communicate with each other.

Referring to Figure 7, a data flow of one embodiment of a call steering method based on the call steering system of Figure 5 is illustrated. As shown, a call turn includes the following steps:

1. UE 100 and UE 200 have established a first call contact. In the home network of the UE 200, the AS 210 is a second serving network element (which is a B2BUA network element) in the signaling path of the call, and the session identifier to the UE 100 side is Dialog- lc, and the session identifier is set to the UE 200 side. Dialog-2; In the home network of the UE 100, the AS 110 is a second serving network element (which is a B2BUA network element) in the signaling path of the call, and the session identifier to the UE 100 side is Dialog-lb, The session identifier on the UE 200 side is Dialog- lc.

2. The UE 300 sends a call steering instruction to the UE 200, where the command includes the UE 200 identifier. Specifically, the command is a first SEP REFER message, and the UE 200 is required to send a second SIP REFER message to the UE 100, where the command is further carried. The process of obtaining the session status of the UE 200 by the UE is as described above, and is not described in detail in this embodiment. In the obtained session, in addition to the Dialog-2 session identifier, there is also the user ID of the UE 100, which is the first user of the UE 200.

3. The B2BUA network element AS210 in the home network of the UE 200 receives the first SIP REFER message sent by the UE 300, and according to the message request, sends a second SIP REFER message to the UE 100, and the second REFER message will request the UE 100 to resend the message to the UE 300. a third SIP REFER According to the B2BUA mechanism, the session identifier carried in the second REFER message is Dialog-lc corresponding to Dialog-2.

4. The B2BUA network element AS110 in the home network of the UE 100 receives the second SIP REFER message, and according to the message request, sends a third SIP REFER message to the UE 300, and the third REFER message will request the UE 300 to send a SIP INVITE message to the UE 100. The third REFER message still carries the Dialog-lc identifier.

It should be noted that there may be other B2BUA network elements between the AS 110 and the AS 210 located in the call signaling path established by the UE 100 and the UE 200. At this time, the second REFER message will arrive at the AS 110 along the signaling path. After a B2BUA network element, the network element replaces the session identifier to be replaced in the second REFER message with the session identifier of the network element facing the UE 100 side. For example, a B2BUA network element exists between the AS 110 and the AS 210. The session identifier between the network element and the AS 210 is Dialog-lc, and the session identifier between the AS 110 and the AS 110 is Dialog-lc'. After the second REFER message arrives at the network element, The Dialog-1c is replaced by Dialog-1c by the network element, and the second REFER message is sent to the AS110.

In summary, the session identifier to be replaced carried in the second REFER message arriving at AS 110 is

The AS 110 is directed to the session identifier on the UE 200 side.

It can be seen that, in step 2 to step 4, the first REFER message can be regarded as the call steering instruction of the UE 300 by using three mutually associated REFER messages, and the two REFER messages enable the home network of the UE 200 to pass the attribution of the UE 100. The network returns the session identifier of the UE100's home network to the UE 200 (the Dialog-lc in this example) to the UE 300, so that the UE 300 can correctly establish a connection with the UE 100 during the subsequent establishment of a new call with the UE 100. In this embodiment, Dialog-lc is sent from the AS 210 to the AS 110 along the next call signaling path by the second and third REFER messages, and the AS 110 transmits to the UE 300.

5. The ΌΕ300 receives the third REFER message, according to the message request, initiates a new call to the UE 100 (which may be referred to as a second call), and sends a SIP INVITE message carrying the Dialog-lc Session ID.

The AS 110 receives the INVITE message from the UE 300, and according to the B2BUA mechanism, obtains the session identifier of the call on the side of the UE 100 by the Dialog-lc session identifier as Dialog-lb, according to the SDP information of the UE 300 carried in the received INVITE message. The session corresponding to the Dialog-lb session identifier is redirected to the UE 300, and the SIP re-INVITE re-invitation message is sent.

The INVITE message is the call steering command to the AS 110 for the AS 110.

7. The session Dialog-lb redirection is completed, and the UE 100 is redirected from the UE-oriented connection to the UE 300 connection. The specific process is omitted.

8. The second call setup between the AS 110 and the UE 300 is completed, and the corresponding session identifier is Dialog-la. The specific process is omitted.

9. Release the session Dialog-lc, eight 8100 to! 3⁄4200 send 81? 8¥£ goodbye message.

10. Session Dialog-lc is released.

11. The AS 210 receives the SIP BYE message, releases the session Dialog-2, and sends a SIP BYE message to the UE200.

12. The session Dialog-2 is released and the UE 200 exits the call with the UE 100.

In the foregoing embodiment, the second and third REFER messages are used by the home domain network of the UE 200 to reach the home domain network of the UE 100 along the signaling path of the first call, thereby obtaining the home domain network that can be identified by the UE 100, to be The flow of the alternative session identifier is only an example, and other methods may be adopted. As long as the call forwarding instruction sent by the UE 300 is used, the subsequent message flow required by the instruction may reach the home domain network of the UE 100, and the UE 100 may be obtained by the UE 100. The session identifier to be replaced by the home domain network can be replaced.

Specific Embodiment 4:

Referring to Figure 8, a data flow of another embodiment of a call steering method based on the call steering system of Figure 5 is illustrated. As shown, a call turn includes the following steps:

1. The UE 100 and the UE 200 have established a first call contact, in the home domain network of the UE 200, As the second serving network element (which is a B2BUA network element), the AS 210 is located in the signaling path of the call, and the session identifier to the UE 100 side is Dialog-lc, and the session identifier to the UE 200 side is Dialog-2; In the home network, AS 110 is the second service network element (which is a B2BUA network element) in the signaling path of the call, and the session identifier to the UE 100 side is Dialog-lb, and the session identifier to the UE 200 side is Dialog- Lc.

2. The UE 300 sends a call steering instruction to the UE 200, where the command includes the UE 200 identifier. Specifically, the command is a first SIP REFER message, and the UE 200 is required to send a second SIP REFER message to the UE 100, where the command is further carried. The alternative session identifier Dialog-2, the process by which the UE 300 obtains the session condition of the UE 200 is as described above, and this embodiment is omitted.

3. The B2BUA network element in the home network of the UE 200 receives the first one sent by the UE 300.

The SIP REFER message, according to the message request, is to send a second SIP REFER message to the UE 300. At this time, the AS 210 does not immediately send the second REFER message to the UI 300, because the second REFER message is sent according to the request of the UE 300. The REFER message will require the UE 300 to send a new INVITE message to the UE 100, and the session identifier Dialog-2 carried in the first REFER message is on the side of the UE 200, not on the side of the UE 100. Therefore, the AS 210 needs to be first acquired by the AS 110. The identified session identifier, the AS 210 will send a SIP SUBSCRIBE message to the UE 100, where the Event header field carries the dialog event packet.

4. The B2BUA network element in the home network of the UE 100 receives the SUBSCRIBE message from the AS210, and returns a SIP NOTIFY message carrying the Dialog-lc session identifier.

5. The AS 210 sends a second SIP REFER message to the UE 300, and the UE 300 is required to send an INVITE message to the UE 100, where the second REFER message carries the Dialog-1c identifier.

It can be seen that, in step 3-5, the home network of the UE 200 returns the session identifier (Dialog-lc in this example) of the home network of the IJE 100 to the UE 200 through the home network of the UE 100, so that the UE 300 is in the subsequent A connection can be established correctly with the UE 100 during the establishment of a new call with the UE 100. In this embodiment, Dialog-lc is obtained by AS 210 from AS 110 and then forwarded to UE300.

6. The UE 300 receives the second REFER message, and sends a SIP INVITE message to the UE 100 according to the message request, where the message carries the Dialog-lc session identifier.

7. The AS 110 receives the INVITE message from the UE 300. According to the B2BUA mechanism, the session identifier of the call where the Dialog-lc session identifier is located on the side of the UE 100 is Dialog-lb. According to the SDP information of the UE 300 carried in the received INVITE message, The session corresponding to the Dialog-lb session identifier is redirected to the UE 300, and a SIP re-INVITE re-invitation message is sent.

The INVITE message is the call steering command to the AS 110 for the AS 110.

8. The session Dialog-lb redirection is completed, and the UE 100 is redirected from the UE-oriented connection to the UE 300 connection. The specific process is omitted.

9. The call setup between the AS 110 and the UE 300 is completed, and the corresponding session identifier is Dialog la, and the specific procedure is omitted.

10. Release the session Dialog-lc, AS 110 sends a SIP BYE goodbye message to UE200.

11. Session Dialog-1c is released.

12. The AS 110 receives the SIP BYE message, releases the session Dialog-2, and sends the SIP to the UE200.

BYE message.

13. The session Dialog-2 is released and the UE 200 exits the call with the UE 100.

It should be noted that the call steering instructions in the foregoing embodiments are merely examples. In addition to the SUBSCRIBE, INVITE, REFER, and the like, other operations may be performed, such as by using an HTTP message.

In addition, the call steering instruction in the various embodiments and the process of the triggering thereof do not mean that it can only be applied to the method in which the example is located, and the REFER operations as exemplified in the third and fourth embodiments can also be applied to the first and second embodiments. The UE 300 sends a SIP REFER message to the UE 200, and the message is required to send a SIP INVITE message to the UE 300. The caller of the INVITE message is the UE 100. The message example is as follows: REFER UE200

Refer-To:

UE300 (method=INYITE?From=UE100?To=UE300?Replaces=Dialog-2) The AS210 receives the REFER message, and according to the message request, the UE 100 sends a new SIP INVITE message to the UE 300, and the message carries The STP information of the UE 100, the AS 210 sends a SIP re-INVITE message to the UE 100, and redirects the session that the call of the Dialog-2 session is in the UE 100 and the AS 210 to the UE 300; or, if the REFER message sent by the UE 300 is directly carried, For the SDP information of the UE 300, the AS 210 may first redirect the UE 100, and the re-INVITE message sent to the UE 100 carries the SDP information of the UE 300, and then sends a new INVITE message carrying the SDP information of the UE 100 to the UE 300. The specific process is omitted. It can be seen that at this time, the call forwarding instruction sent by the UE300 does not carry the call forwarding service identifier.

For example, in the third and fourth embodiments, a new INVITE call may be initiated by the UE 100's home network to the UE 300, as in the first and second embodiments. For example, in the third and fourth embodiments, the second REFER message is sent. The AS 110, the AS 110 sends a new call to the UE 300 according to the second REFER message, and sends a SIP INVITE message, where the message carries the SDP information of the UE 100, and establishes a call connection with the UE 300, and carries the call according to the received second REFER message. The replaced Dialog- lc identifier redirects the session corresponding to the Dialog- lb identifier corresponding to the Dialog- lc identifier to the UE 300 according to the B2BUA mechanism. The example of the second REFER message is as follows:

REFER UE100

Refer-To: UE300 (method=INVITE?Replaces=Dialog- 1 c)

At this time, the second REFER message is the call steering instruction of the AS 110 for the AS 110. The specific process is omitted.

For example, the call forwarding service identifiers described in Embodiments 1 and 2 can also be applied in Embodiments 3 and 4. Embodiments 3 and 4 can also be selected by the home network from the established user. An alternative session identifier, in the third and fourth embodiments, the call steering command sent by the UE 300 may also be To carry the SDP information of the UE 300.

In addition, the call forwarding service identifiers in the foregoing Embodiments 1 and 2 are merely examples. In addition to the extended pickup event packet, other indication manners, such as a header field, a message body parameter, or a Request - Uniform Resource Identifier (Request-URI), etc.

It can be seen that the call control signaling used in the foregoing Embodiments 1 to 4 is SIP signaling.

It can be seen that the key technologies of the foregoing Embodiments 1 and 2 are: according to the call steering instruction initiated by the third party user, the home network of the substitute user and the third party user establish a new call contact, and the established call relationship with the redirected user is established. The session is redirected to a third-party user and then quit the replaced user.

The key technologies of the third and fourth embodiments are: according to the call steering instruction initiated by the third party user, the user's home network is redirected to the third party user to establish a new call contact, and the established session with the redirected user is redirected to Third-party users, then quit the replaced user. In this case, the home network of the replaced user and the home network of the redirected user may first establish a new call contact with the third party user, and then initiate a redirect request; or may initiate a redirect request first, and then establish a new call to the third party user. Call contact; it is also possible to initiate a redirect request and establish a new call contact to a third party user.

The above-mentioned call steering occurrence scenario is that after the substitute user and the redirecting user have established the call contact, the third party user initiates the call steering instruction. In addition, as described above, the scene of the call steering may also be turned to the user or The substitute user initiates the call steering instruction. According to the analogy of the method in the above embodiment, for the latter scenario, the new call of the third party user may be established by the replaced user or the home network of the user. The session that has been established between the redirected users is redirected to the third-party user and then exited by the alternate user. Because it is a call steering instruction initiated by the user or the substitute user, the session identifier to be replaced or the substitute user side to be replaced may be directly carried in the instruction, and the call forwarding instruction takes the REFER message as an example, and the session identifier is taken as an example. As shown in FIG. 8 , an example of a message sent by the UE 200 is as follows: REFER UE100

Refer-To: UE300 (method=INVITE?Replaces=Dialog-2)

The AS 110 in the home network of the UE 100 receives the REFER message, initiates a new call to the UE 300, and sends an INVITE message, which carries the SDP information of the UE 100, and then sends a re-INVITE message to the UE 100, which is established with the UE 100. The session ( Dialog-lb ) is redirected to the UE 300, after which the sessions Dialog- lc and Dialog-2 are released. That is, a new call contact is established to the third party user by the home network that turns to the user and a redirect request is initiated.

The AS 210 in the home network of the UE 200 may receive the REFER message, initiate a new call to the UE 300, and send an INVITE message, where the message carries the SDP information of the UE 100, and then sends a re-INVITE message to the UE 100, which will be associated with the UE 100. The established session (Dialog-lc) is redirected to the UE 300, after which the session Dialog-2 is released. That is, a new call contact is established by the home network of the replaced user to the third party user to initiate the redirect request.

Or, an example of a message sent by the UE 100 is as follows:

REFER UE200

Refer-To: UE300 (method=INVITE?Replaces=Dialog- 1 b)

The AS 210 in the home network of the UE 200 receives the REFER message, initiates a new call to the UE 300, and sends an INVITE message, which carries the SDP information of the UE 100, and then sends a re-INVITE message to the UE 100, which is established with the UE 100. The session ( Dialog-lc ) is redirected to UE 300, after which session Dialog-2 is released. That is, a new call contact is established to the third party user by the home network of the replaced user and a redirect request is initiated.

The AS 110 in the home network of the UE 100 may receive the REFER message, initiate a new call to the UE 300, and send an INVITE message, where the message carries the SDP information of the UE 100, and then sends a re-INVITE message to the UE 100, which will be associated with the UE 100. The established session (Dialog-lb) is redirected to the UE 300, after which the sessions Dialog-lc and Dialog-2 are released. That is, a new call contact is established to the third party user by the home network that is turned to the user to initiate the redirect request. In the subsequent message flow of the call forwarding instruction, the session identifier is replaced by a back-to-back session identifier by the substitute user or the home network of the redirected user according to the B2BUA mechanism.

In order to implement the above redirection function, the session identifiers to be replaced obtained by the home network of the substitute user and the home network of the redirected user are all session identifiers that they can identify and are oriented to the replaced user side, so as to Identify back-to-back session redirection for the corresponding session. The session identifier obtained by the home network of the substitute user is referred to as a first session identifier, and the session identifier obtained by the home network of the user is referred to as a second session identifier, and may be the first session for the home network of the replaced user. The identification is sent to the home network of the replaced user by the call forwarding instruction, or the other session identifier of the call where the first session identifier is located is sent to the home network of the replaced user by the call forwarding instruction, and the home network of the replaced user obtains the first according to the B2BUA mechanism. For example, the home network of the substitute user obtains the first session identifier from the current session situation of the replaced user, and the home network of the replaced user may turn to the service identifier or turn to the user terminal according to the call carried in the call steering instruction. The identifier of the session is obtained from the current session of the user being replaced; and for the home network that is redirected to the user, after the first session identifier is obtained by the home network of the substitute user, The signaling path of the call is routed to the steering user The manner of the home network, or the manner in which the call where the session identifier is located is redirected to the user's home network, to obtain the second session identifier, or the second session identifier is sent to the home network of the redirected user by the call forwarding command, or The other session identifier of the call where the second session identifier is located is sent to the home network of the redirecting user by using the call forwarding instruction, and the home network that is turned to the user obtains the second session identifier according to the B2BUA mechanism.

A person skilled in the art can understand that all or part of the steps of implementing the above embodiments can be completed by a program to instruct related hardware, and the program can be stored in a computer readable storage medium shield. When executed, the method includes the following steps: receiving, by the home network of the substitute user terminal, a first call steering instruction, where the first call steering instruction includes at least an identifier of the third-party user terminal, and the home network of the replaced user terminal is configured according to the a first call steering instruction, establishing a second party call of the third party user terminal to the redirecting user terminal, and ending the steering user The session is redirected to the third-party user terminal for the session that has been established by the replaced user terminal; the storage medium, such as: ROM/RAM, disk, optical disk, and the like.

The above is only the preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, and the equivalent changes made by the scope of the present invention remain within the scope of the present invention.

Claims

Rights request

A method for implementing call forwarding, the first call is established between the user terminal and the replaced user terminal, and the method includes the following steps:

2. The method according to claim 1, further comprising the step of: the home network of the replaced user terminal withdrawing the replaced user terminal from the first call.

3. The method according to claim 1, further comprising

The home network of the replaced user terminal acquires the session identifier of the session to be replaced.

The method according to claim 3, wherein the step of obtaining the session identifier of the session to be replaced by the network of the replaced user terminal comprises:

The first call forwarding instruction includes a session identifier of the first call, and the home network of the replaced user terminal acquires a session identifier of the session to be replaced according to the session identifier of the first call; or ,

The home network of the replaced user terminal acquires a session identifier as the session identifier of the session to be replaced in the session currently established by the replaced user terminal.

The method according to claim 4, wherein the home network of the replaced user terminal acquires a session identifier as a session identifier of a session to be replaced in a session currently established by the replaced user terminal. The steps specifically include:

The first call steering instruction includes a call forwarding service identifier, and the home network of the replaced user terminal acquires a session identifier in the tongue that is currently established by the replaced user terminal according to the call forwarding service identifier. The session ID of the replaced session; or, The first call steering instruction includes an identifier of the user terminal, and the home network of the replaced user terminal acquires a session identifier in the session currently established by the replaced user terminal according to the identifier of the redirected user terminal. The session ID of the session to be replaced.

The method according to claim 4, wherein the step of the home network of the replaced user terminal acquiring the session identifier of the session to be replaced according to the session identifier of the first call specifically includes:

The home network of the replaced user terminal directly uses the session identifier of the first call as the session identifier of the session to be replaced; or

The home network of the replaced user terminal uses the other session identifiers located in the same call as the session identifier of the first call as the session identifier of the session to be replaced according to the B2BUA mechanism.

The method according to any one of claims 1 to 6, wherein: the first call forwarding instruction further includes session description protocol information of the third-party user terminal.

The method according to any one of claims 1 to 6, wherein: the first call steering instruction is sent to the home by the redirected user terminal, the replaced user terminal or the third party user terminal The home network of the replaced user terminal.

A method for implementing call forwarding, the first call being established between the user terminal and the replaced user terminal, wherein the method comprises the following steps:

Receiving, by the home network of the user terminal, a first call steering instruction, where the first call forwarding instruction includes at least an identifier of the third-party user terminal;

10. The method of claim 9 further comprising

The home network that is diverted to the user terminal exits the replaced user terminal from the first call.

11. The method according to claim 9, further comprising The home network that turns to the user terminal acquires the session identifier of the session to be replaced.

The method according to claim 11, wherein the step of redirecting the session identifier of the session to be replaced by the attribution network of the user terminal comprises:

The call forwarding instruction includes a session identifier of the first call, and the home network that turns to the user terminal acquires the session identifier of the session to be replaced according to the session identifier of the first call.

The method according to claim 12, wherein the step of the local network that is redirected to the user terminal to obtain the session identifier of the session to be replaced according to the session identifier of the first call includes:

The home network that is turned to the user terminal uses the session identifier of the first call as the session identifier of the session to be replaced; or

The home network that is redirected to the user terminal uses the other session identifiers in the same call as the session identifier of the first call as the session identifier of the session to be replaced according to the B2BUA mechanism.

The method according to any one of claims 9 to 13, characterized in that: the first call steering instruction is sent by the steering user terminal or the replaced user terminal to a home network of the steering user terminal Or,

The third-party user terminal initiates a second call-steering instruction, and the subsequent message flow that is sent to the home network of the user terminal by the second call-steering instruction is used as the first call-steering instruction.

The method according to claim 14, wherein the third party user terminal initiates a second call steering instruction, and the home network of the redirecting user terminal uses a subsequent message flow performed by the second call steering instruction as The step of the first call steering instruction includes:

After the home network of the replaced user terminal performs the second call steering instruction from the third party user terminal, the second subsequent message flow executed by the second call steering instruction is sent to the home network of the redirected user terminal, After performing the first subsequent message flow, the home network that is turned to the user terminal sends the executed second subsequent message flow to the third-party user terminal, where the third-party user terminal After performing the second subsequent message flow, sending, to the home network of the user terminal, the executed third subsequent message flow, where the home network that turns to the user terminal uses the third subsequent message flow as the first call Steering instruction; or,

After the home network of the replaced user terminal performs the second call forwarding instruction from the third-party user terminal, sending the executed first subsequent message flow to the third-party user terminal, where the third-party user terminal performs the After the first subsequent message flow, sending the executed second subsequent message flow to the home network that is redirected to the user terminal, where the home network that is redirected to the user terminal uses the second subsequent message flow as the first call steering instruction; Or,

After performing the second call steering instruction of the third-party user terminal, the home network of the replaced user terminal sends the executed first subsequent message flow to the home network of the user terminal, and the home network of the user terminal is transferred. The first subsequent message flow is used as the first call steering instruction.

The method according to claim 15, further comprising the steps of: the home network of the replaced user terminal carrying the session identifier of the session to be replaced in the first subsequent message flow, The session ID of the session to be replaced is obtained by one of the following methods:

The home network of the replaced user terminal acquires the session identifier of the session to be replaced according to the received session identifier of the first call included in the second call forwarding instruction; or, the replaced user terminal The home network subscribes to the home network that is redirected to the user terminal to obtain the session identifier of the session to be replaced; or

The method according to claim 14, wherein the second call forwarding instruction further comprises at least one of session description protocol information, a call forwarding service identifier, and an identification of a redirected user terminal of the third-party user terminal. .

18. A home network of a user terminal, which has been established between the user terminal and the replaced user terminal The first call is set, which is characterized by:

a receiving unit, configured to receive a call steering instruction, where the call steering instruction includes at least an identifier of the third party user terminal;

19. The home network of claim 18, wherein the call unit is further configured to exit the replaced user terminal from the first call.

The home network according to claim 18, further comprising an obtaining unit, configured to acquire, according to the call steering instruction, a session identifier of a session to be replaced and send the session identifier to the call unit.

The home network according to any one of claims 18 to 20, further comprising an execution unit, configured to execute the call steering instruction, and generate a new call steering instruction, carrying the third party user terminal The identity is sent to the calling unit.

The home network according to claim 21, wherein the acquiring unit sends the acquired session identifier of the session to be replaced to the execution unit, and is carried by the new call steering instruction. The call unit sends.

23. A system for implementing call steering, comprising a diverting user, an alternate user, and a third party user, the diverting user comprising a diverting user terminal, the replaced user comprising an alternate user terminal and being coupled to the replaced user terminal The service network element, the third-party user includes a third-party user terminal, and the redirected user, the replaced user, and the third-party user are coupled to each other, and can communicate with each other, and switch between the user terminal and the replaced user terminal. A first call has been established, which is characterized by:

The service network element is configured to establish, according to the call steering instruction, the third-party user terminal plane And redirecting the second call to the user terminal and redirecting the redirected user terminal to the third user terminal to the session that has been established by the replaced user terminal.

The system according to claim 23, wherein the serving network element is further configured to exit the replaced user terminal from the first call.

25. A system for implementing call forwarding, comprising a redirected user, a replaced user, and a third party user, the redirected user comprising a redirected user terminal and a first serving network element coupled to the redirected user terminal, the replaced The user includes the replaced user terminal and the second service network element coupled to the replaced user terminal, the third party user includes a third-party user terminal, and the redirected user, the replaced user, and the third-party user Coupling, can communicate with each other, and the first call has been established between the user terminal and the replaced user terminal, and is characterized by:

The second service network element is configured to send a subsequent message flow obtained according to the call forwarding instruction to the first service network element or the third-party user terminal;

The first service network element is configured to establish a second call of the third-party user terminal to the redirected user terminal, and redirect the redirected user terminal to a session that has been established by the replaced user terminal to The third party user terminal.

The system according to claim 25, wherein the first serving network element is further configured to exit the replaced user terminal from the first call.