KR20080016080A - Method for call processing in combination of cs and ims services - Google Patents

Abstract

A call processing method in CSI(Combination of CS and IMS Services) is provided to be capable of confirming connection between an invite message for an IMS(IP Multimedia Subsystem) session and a CS(Circuit Switched) call by using time information, even though frequent connection and termination between the CS call and the IMS session occur, thereby preventing an error of processing or notifying of incorrect IMS call arrival. A CS call is connected(S500). The first message which demands IMS session formation including time information is received(S505). In reference to the time information, it is decided whether the first message is originated before the CS call is connected(S510,S515). If so, the IMS session formation is rejected(S520). If the first message is originated after the CS call is connected, the second message for approving of the IMS session formation is transmitted(S525).

Description

Method for call processing in combination of CS and IMS services}

1 is a diagram illustrating an example of a CSI system to which a call processing method according to the present invention is applied;

2 and 3 are message sequence charts provided in the description of the call processing method in the CSI according to an embodiment of the present invention, and

4 is a flowchart provided to explain a call processing method in CSI according to an embodiment of the present invention.

Explanation of symbols on the main parts of the drawings

100: first user device 200: second user device

The present invention relates to a call processing method in the CSI (Combination of CS and IMS Services), and more particularly, to a call processing method in the CSI that checks the connectivity between the CS call and the IMS session to prevent an error indicating an invalid IMS call arrival. It is about.

IP Multimedia Subsystem (IMS), introduced in 3rd Generation Project (3GPP) Release 5, is an open architecture that enables IP multimedia services in mobile, wired, and converged environments, providing new services in all-IP-based next-generation communication environments. It is attracting attention as a key technology for doing so. IMS is based on the Internet Engineering Task Force (IETF) specification and is independent of radio access networks such as EDGE, WCDMA, HSDPA, 802.11a / b / g and Wibro. In addition, IETF Session Initiation Protocol (SIP) is used as signaling between a user equipment (UE) and a core network in a IMS.

A CSI (Combination of CS and IMS Services) is a service that provides a combination of IMS services based on such IMS and CS (Circuit Switched) call processing. That is, in CSI, a service that requires real time such as a voice call uses a CS call and another IMS service for a multimedia service that does not require relatively real time.

However, in a typical CSI system, SIP used for signaling in an IMS service uses UDP (User Datagram Protocol). However, if UDP is used for signaling in the IMS service, a message may be received that is not related to the currently connected CS call depending on the IP network situation. That is, it is impossible to distinguish whether a message arriving after the CS call is connected to the existing voice call, that is, a message originating from a CS call or a message connected to a previously connected voice call. An error may occur that informs the arrival of a message that is not associated with a.

Accordingly, an object of the present invention is to provide a call processing method in a CSI that can prevent an error in processing an invalid IMS call by checking whether a message arriving after a CS call connection in a CSI is related to a currently connected CS call. Is in.

Call processing method in the CSI according to the present invention for achieving the above object, the step of connecting a CS (Circuit Switched) call, receiving a first message requesting the formation of an IP Multimedia Subsystem (IMS) session including time information Determining whether the first message is a message sent before the CS call connection with reference to the time information, and rejecting the IMS session establishment when the first message is a message sent before the CS call connection; It includes a step. In addition, when the first message is a message originated after the CS call connection, a second message for accepting the IMS session establishment may be transmitted.

In addition, the call processing method in the CSI according to the present invention for achieving the above object, the step of connecting a CS (Circuit Switched) call between the calling user device and the receiving user device, the calling user device is IMS (IP Multimedia) Subsystem) including the time information in the service request message and transmitting the time information to the receiving user device, and comparing the time information included in the request message with the time the CS call is connected in the receiving user device, Determining whether to accept the IMS service request.

In order to achieve the above object, the present invention provides a processor-readable recording medium having recorded thereon a program for executing the method in a processor in a user equipment.

Hereinafter, with reference to the drawings will be described the present invention in more detail.

1 is a diagram illustrating an example of a CSI system to which a call processing method according to the present invention is applied. As shown in FIG. 1, the first user equipment (UE-A) 100 and the second user equipment (UE-B) 200 are CS cores 120 and 220 through the access networks 110 and 210, respectively. ) And the IMS cores 130 and 240 network. Through this, the CS call and the IMS call can be simultaneously connected, and a service requiring a real time such as a voice call can use a CS call, and other multimedia services that do not require a relatively real time can use an IMS call. If necessary, the application servers (AS) 150 and 250 may be used for IMS side control.

 2 and 3 are message sequence charts provided to explain a call processing method in CSI according to an embodiment of the present invention. First, referring to FIG. 2, after a CS call is connected between UEs, a process of checking IMS capability information of the counterpart device in order to use an IMS service will be described.

The first user equipment UE-A transmits a SIP OPTIONS message through the IMS core A (S300), and the IMS core A forwards it to the IMS core B (S305). In the IMS core B, the path is determined based on the selection of the calling party, the performance of the receiving party, etc. (S310), and the OPTIONS message is forwarded to the second user equipment UE-B (S315). The second user equipment UE-B stores address information of the first user equipment UE-A (S320), and transmits a 200 OK message including the performance information to the IMS core B. The IMS core B forwards the 200 OK message to the IMS core A (S330), and the IMS core A forwards the 200 OK message to the first user device UE-A (S335). The first user equipment UE-A updates or stores the received performance information in operation S340.

Through this process, the first user equipment UE-A may check performance information of the second user equipment UE-B, and the second user equipment UE-B may also identify the first user by the same process. You can check the performance of the device (UE-A).

 3 is a message sequence chart for explaining a process of starting an IMS service after confirming performance information of a counterpart user device after connecting a CS call between user devices. Referring to FIG. 3, after a CS call connection between two user equipments UE-A and UE-B (S400), IMS performance information on the counterpart user equipment may be exchanged (S405).

Then, the first user equipment UE-A transmits an INVITE message to the IMS core A to start the IMS service (S410 and S415). The IMS core A forwards the INVITE message to the IMS core B (S420), and the IMS core B forwards the INVITE message to the second user equipment UE-B (S425). When the second user equipment UE-B accepts the IMS service (S430), a 200 OK message is transmitted to the IMS core B (S435), and the IMS core B sends a 200 OK message to the IMS core A. Forwarding (S440), the IMS core (A) is forwarded back to the first user equipment (UE-A) (S445). The first user equipment UE-A transmits an ACK for this to the second user equipment UE-B through the IMS core A and the IMS core B (S450, S455, and S460). An IMS session, that is, a media session is formed (S465).

In this process, in the call processing method according to the present invention, in order to determine whether an INVITE message related to a currently connected voice call, that is, a CS call is delivered, GMT (Greenwich Mean) in the header of an INVITE message requesting the formation of an IMS session. Time) Insert information and send. In this case, the GMT information may be inserted in the calling user equipment or the calling party P-CSCF. The user equipment of the receiver of the INVITE message may determine whether to accept the IMS formation by checking the GMT information of the origination in the header of the received INVITE message and comparing it with the connection time of the currently connected CS call. This will be described in more detail with reference to FIG. 4.

4 is a flowchart provided to explain a call processing method in a receiving user device in the call processing method according to the present invention. Referring to FIG. 4, after the CS call is connected (S500), it is determined whether an INVITE message for requesting IMS session establishment is received, and when an INVITE message is received (S505), GMT (Greenwich) included in the header of the INVITE message is determined. Mean Time) information is checked (S510).

As a result of checking the GMT information that is the time information, if the received INVITE message is a message sent before the CS call connection, the SIP 403 "Forbidden" response message that rejects the INVITE request is transmitted (S520) or ignored. In this case, since the request for IMS session establishment is rejected, the IMS session cannot be established.

On the contrary, if the received INVITE message is a message sent after the CS call is connected as a result of checking the GMT information, a 200 OK message is transmitted with respect to the INVITE message (S525). In this case, an IMS session is established and the IMS service can be used.

By this process, in response to the IMS service sent before the CS call connection, an error in processing an IMS call not related to the CS call currently connected can be prevented.

On the other hand, the present invention may be implemented in a processor-readable code on a recording medium that can be read by a processor in a user equipment such as a mobile station modem (MSM) chip. Examples of the processor-readable recording medium may include a ROM, a RAM, a flash memory, a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, and may also be implemented in the form of a carrier wave such as a transmission through the Internet. It includes being. In addition, the processor-readable medium may be distributed and stored in a network connected computer system so that the processor-readable code may be stored and executed.

In addition, although the preferred embodiment of the present invention has been shown and described above, the present invention is not limited to the specific embodiments described above, but the technical field to which the invention belongs without departing from the spirit of the invention claimed in the claims. Of course, various modifications can be made by those skilled in the art, and these modifications should not be individually understood from the technical spirit or the prospect of the present invention.

As described above, according to the present invention, even if the frequent connection and termination of the CS call and the IMS session are repeated, since the connectivity between the CS call and the INVITE message for the IMS session can be confirmed using the time information, the wrong IMS call You can avoid errors that inform or handle arrivals.

Claims (11)

Connecting a CS (Circuit Switched) call; Receiving a first message requesting establishment of an IP multimedia subsystem (IMS) session including time information; Determining whether the first message is a message sent before the CS call is connected with reference to the time information; And And if the first message is a message sent before the CS call connection, rejecting the IMS session establishment. The method of claim 1, And if the first message is a message originated after the CS call connection, transmitting a second message that accepts the IMS session establishment. The method of claim 2, Receiving an ACK message for the second message. The method of claim 1, In the rejecting step, the method for processing a call in the CSI, characterized in that to reject the IMS session establishment by sending a 403 response message. The method of claim 1, And the first message is an INVITE message. The method of claim 5, And the time information is GMT information included in a header of the INVITE message. The method of claim 1, The time information is a call processing method in the CSI, characterized in that any one of the source user equipment and the source P-CSCF (Proxy-CSCF) is inserted. The method of claim 1, Exchanging IMS performance information before requesting the IMS session establishment. Connecting a CS (Circuit Switched) call between the calling user device and the receiving user device; Transmitting, by the calling user device, to the receiving user device by including time information in an IMS (IP Multimedia Subsystem) service request message; And And determining whether to accept the IMS service request according to a result of comparing the time information included in the request message with the time at which the CS call is connected, at the receiving user device. The method of claim 9, The receiving user device rejects the IMS service request if the request message was sent before the CS call connection, and accepts the IMS service request if the request message was sent after the CS call connection. Call processing method in CSI. A processor-readable recording medium having recorded thereon a program for executing the method of claim 1 on a processor.

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