KR20080077809A - Emergency call processing method, device and system in IP-based multimedia subsystem - Google Patents

Abstract

The present invention relates to a call processing method, apparatus and system for emergency calls in an IMS network. When a first emergency call originated by a user terminal in an IMS network is connected with a first call processing terminal, the user terminal is approved by the first call processing terminal. Save the identifier. If the second emergency call is transmitted with the same request URI as the first emergency call after the call of the first emergency call is interrupted due to a communication error, etc., the user terminal includes a second emergency call including call information including the stored approval identifier. Call so that the second emergency call can be connected to the first call processing terminal. As a result, the emergency call can be maintained and the response to the emergency can be made quickly.

Description

METHOD, APPARATUS AND SYSTEM FOR PROCESSING A EMERGENCY CALL IN AN IP MULTIMEDIA SUBSYSTEM}

1 is a general configuration diagram of an IMS network for processing an emergency call sent by a user terminal.

2A and 2B are call processing diagrams illustrating a call processing process when an emergency call is interrupted in a conventional IMS network;

3 is a configuration diagram of a UE connected to an IMS network according to an embodiment of the present invention.

4A and 4B are flowcharts illustrating a call processing method when an emergency call is interrupted in an IMS network according to an embodiment of the present invention.

5A and 5B are call processing diagrams illustrating a call processing method when an emergency call is interrupted in an IMS network according to an embodiment of the present invention.

6A and 6B are call processing diagrams illustrating a call processing method when an emergency call is interrupted in an IMS network according to another embodiment of the present invention.

The present invention relates to a call processing technique in a communication network. More particularly, the present invention relates to a method, apparatus and system for emergency call processing in an IMS (IP Multimedia Subsystem) network.

IMS refers to a service that provides a variety of multimedia information such as voice, audio, video and data to mobile subscribers using an IP (Internet Protocol) based packet network. In accordance with the recent development of mobile communication and the Internet, 3GPP (3 Generation Partnership Project) has standardized all IP-based network reference models to provide communication services in IMS networks. Doing.

 Emergency Calls are calls for help in emergencies such as fire, emergency, and theft. For example, a call sent to 119 or 112, which is an emergency rescue number. When the emergency call is connected to a Public Safety Answering Point (PSAP), a call center dedicated to handling the emergency call, an action corresponding to the emergency call is taken. The IMS network can also handle emergency calls originated by the user terminal in conjunction with PSAP.

1 is a general configuration diagram of an IMS network for processing an emergency call sent by a user terminal.

FIG. 1 assumes a state in which an emergency call originated by a UE 110 is connected to a public safety answering point (PSAP) 130 through an IMS network 120. The user terminal is called various names such as a UE, an access terminal (AT), etc. according to the type of system, but for convenience, the user terminal will be referred to as a UE.

The PSAP 130 is a dedicated call processing center for emergency calls as described above. The PSAP 130 may include a plurality of call processing terminals for processing an emergency call. In FIG. 1, three call processing terminals A 132, a call processing terminal B 133, and a call processing terminal C ( 134). It also includes an Emergency Center (EC) 131 for receiving emergency calls to assign the emergency calls to the three call processing terminals.

The EC 131 usually uses a random method or a circular method to allocate the received emergency call to the call processing terminal. The random method selects an arbitrary call processing terminal among call processing terminals that are currently idle when an emergency call is received, and allocates the received emergency call, and the recursive method is an idle call processing terminal. The method of allocating the received emergency call processing by selecting one of these in order.

In general, the IMS includes a Call Session Control Function (CSCF) that is responsible for handling a call connected to the IMS, and the CSCF is based on its position and role. (Interrogate) -CSCF (not shown) and S (Serving) -CSCF 122 can be classified. The IMS may also include an Emergency (E) -CSCF 123 that handles emergency calls. Typically I-CSCF is also responsible for call processing in IMS, but the I-CSCF is not shown in FIG. 1 because it is not directly related to the handling of emergency calls.

The P-CSCF 121 is a gateway for the UE 110 to connect to the IMS network 120 for the first time, and the S-CSCF 122 or E (Emergency) -CSCF 123 receives a message received from the UE 110. To pass). That is, when the call originated by the UE 110 is an emergency call, the received message is transmitted to the E-Emergency-CSCF 123. If the call is not an emergency call, the UE 110 transmits the received message to the S-CSCF 122.

The PSAP 130 may exist outside or inside the IMS network 120. When the PSAP 130 exists outside the IMS network 120, the IMS 120 includes a Media Gateway Control Function (MGCF) 124 to process emergency calls sent to the IMS network 120. The MGCF 124 performs media conversion for interworking with the IMS 120 and the external network (ie, the PSAP 130).

If the PSAP 130 exists inside the IMS network 120, the PSAP 130 is directly connected to the E-CSCF 123. 1 is assuming that the PSAP 130 exists outside the IMS network 120.

2A and 2B are call processing diagrams illustrating a call processing process when an emergency call is interrupted in a conventional IMS network.

Hereinafter, a message exchanged between communication entities of the IMS network 120 will be described first. The IMS network 120 uses a Session Initiation Protocol (SIP) for exchanging messages between communication entities connected to the IMS network 120. SIP has a Request / Response structure and can be used with TCP and UDP. In addition, the IMS network 120 may provide a communication service without being dependent on the IP address of the communication entity by using a SIP Uniform Resource Indicator (URI) similar to an email address to distinguish each communication entity.

In step 201, the UE 110 transmits a message <Invite [Request-Uri: sip: sos@ims.com]>. The invite message is for requesting a call connection to a communication counterpart. The invite message also indicates the destination of the message requested by the UE 110 by including a SIP URI similar in form to an email address, such as sip: sos@ims.com.

The call processing terminal B 133 responds to the invite message by transmitting <183 Session Progress [P-Asserted-Identity: sip: line_b@ims.com]> to the UE 110. Specific meanings of the messages described in the above example will be described in the corresponding step.

In FIG. 2, the EC 131, the call processing terminal A 132, the call processing terminal B 133, and the call processing terminal C 134 included in the PSAP 130 send or send a message like the UE 110. Think of it as a user terminal that can receive. In other words, it may be considered to be the same as a general user terminal except for processing an emergency call. Therefore, the call processing terminals 132 ˜ 134 use the protocol used in the IMS 120 as it is to access the IMS network 120.

In step 201, the UE 110 sends an emergency call. That is, in step 201- (1), the UE 110 transmits an invite message to the P-CSCF 121. The invite message includes a "Request-URI" and the request URI means a point (destination) to which a call originated by the UE 110 will arrive. [Request-URI: sos@ims.com] used in step 201 means that the call made by the UE 110 is an emergency call of type sos.

In step 201- (2), the P-CSCF 121 determines that the call originated by the UE 110 is an urgent call based on the request URI, and delivers the invite message to the E-CSCF 123. In step (3), the E-CSCF 123 transmits the invite message to the PSAP 130 that is closest to the UE 110 based on the location information of the UE 110 included in the invite message. Since the E-CSCF searches for the adjacent PSAP 130 is not included in the present invention, a detailed description thereof will be omitted.

In step 201- (4), the EC 131 selects the call processing terminal B 133 by the random method or the cyclic method mentioned above, and selects [Request-URI: sos@ims.com] from [Request-URI: sip: line_b@ims.com]. The invite message is transmitted to the call processing terminal B 133 by the conversion.

In step 203, the call processing terminal B 123 transmits a call permission message (for example, 183 Session Progress) to the UE 110 through the reverse path of step 201 in response to the invite message. . The call admission message includes an P-Asserted-Identity. The approval identifier refers to the number of the terminal that has sent the call admission message. [Sip: line_b@ims.com], which is used as the approval identifier at step 203, has been called by the call processing terminal B 133. It means. The UE 110 receiving the grant identifier may know that the emergency call is connected to the call processing terminal B 133. Then, the user of the UE 110 may request help by explaining his or her emergency to the counselor in charge of the call processing terminal B 133.

By the way, in step 203, the emergency call of the UE 110 is connected to the call processing terminal B 133 of the PSAP 130 in a busy state, and in step 205, the emergency call may be interrupted due to an abnormal communication environment. Can be.

As the emergency call is suspended, the UE 110 again sends a call in step 207. Steps 207- (1) to 207- (3) are the same processes as steps 201- (1) to 201- (3), and thus a detailed description thereof will be omitted. In step 207- (4), the EC 131 transmits an invite message including the request URI [Request-URI: sip: line_c@ims.com] to the call processing terminal C 134. The call processing terminal C 134 is also selected by the random method or the cyclic method.

In step 209, the call processing terminal C 134 transmits a call permission message to the UE 110 through the reverse path of step 207 in response to the invite message of step 207. The call processing terminal C 134 sends the call acceptance message by [sip: line_c@ims.com], which is an approval identifier included in the call admission message, and thus, the call processing terminal C 134 and the emergency call are connected. Able to know.

As described in FIG. 2, when an emergency call made by the user through the IMS 120 is connected with the call processing terminal and the connection of the emergency call is interrupted due to an abnormality in a communication environment, etc., the user sends an emergency call again. It can happen.

In this case, as described above, the EC 131 allocates an emergency call to the call processing terminal by a random method or a cyclic method. Therefore, when a new emergency call is sent after the emergency call is interrupted, the call processing terminal (call processing terminal B 133) and the call processing terminal (call processing terminal C 134) to which the new emergency call is connected may be different. Therefore, there is a problem in that the continuity of the call between the user and the call processing terminal is not maintained and the user must explain his or her emergency situation again.

For example, if an emergency call for reporting an emergency patient is connected to the PSAP, and the user is interrupted while talking to the emergency call handler through the call processing terminal, the user makes an emergency call again and is connected to a new call processing terminal. As a new call processing terminal re-explains the emergency patient to other emergency call processing personnel, there is a problem that the response to the emergency patient is delayed.

One aspect of the present invention to solve the above problems is to provide an emergency call processing method and apparatus and system in the IMS network.

Another aspect of the present invention is to provide a method, apparatus, and system for call processing when an emergency call is interrupted in an IMS network.

Therefore, in the emergency call processing method through an IP Multimedia Subsystem (IMS) network provided by the present invention, a first emergency call originated by a user terminal is preset among a plurality of call processing terminals in an emergency call processing center. When connected with the first call processing terminal selected by the method, the user terminal receives and stores an approval identifier indicating the first call processing terminal, and after the first emergency call is interrupted, transmits the same request URI as the first emergency call. 2 when the emergency call is sent, the user terminal transmits a call request message including the stored approval identifier to the IMS network to send a second emergency call; and the second emergency call is received using the approval identifier. The process of connecting to the first call processing terminal.

In addition, a user terminal for transmitting and receiving a message through an IP Multimedia Subsystem (IMS) network provided by the present invention includes an external interface for transmitting and receiving a signal to and from the IMS network, and a signal transmitted and received through the external interface. A call permission message including a data processing unit for performing modulation and demodulation, and an approval identifier indicating the first call processing terminal when the first emergency call is connected with the first call processing terminal in the emergency call processing center. And a control unit for transmitting a call request message including the approval identifier when the second emergency call is transmitted with the same request URI as the first emergency call after the first emergency call is stopped, and a storage unit for storing the approval identifier. Include.

In addition, the call processing system for processing an emergency call including an IP Multimedia Subsystem (IMS) network provided by the present invention includes a plurality of call processing terminals connected to the IMS network to process the emergency call. An emergency call processing center, a first call processing terminal selected by a preset method among the plurality of call processing terminals, and a first emergency call, and an approval identifier indicating the first call processing terminal; It receives and stores through, and after the first emergency call is abnormally interrupted to send a second emergency call to the same request URI as the first emergency call, and transmits a call request message including the stored approval identifier to the IMS network It includes a user terminal.

Preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

In the following, reference will be made to the network structure of FIG. 1 in describing an operation according to an embodiment of the present invention. However, it should be understood that the emergency call processing according to the embodiment of the present invention is not limited to this network configuration and is applicable to any kind of system using similar network structures and protocols.

3 is a configuration diagram of a UE connected to an IMS network according to an embodiment of the present invention.

The UE 110 may be connected to the IMS network 120 by wire or wirelessly through the external interface unit 302. If the UE 110 is wirelessly connected to the IMS network 120, the external interface unit 302 may process a signal transmitted and received between the IMS network 120 in the form of a radio frequency (RF) signal. have.

The data processing unit 304 performs encoding and modulation of the signal so that the signal is transmitted by wire or wirelessly through the external interface unit 302, and performs a modem function of demodulating and decoding a signal received by wire or wirelessly.

The control unit 308 performs the general control of the UE (110) and receives the approval identifier included in the call permission message transmitted by the call processing terminal B (133) that is the other party to which the emergency call is connected, and the approval identifier is stored in the storage unit (306) Store in

In addition, the control unit 308, after the emergency call is interrupted during a call, a new emergency call is sent with the same request URI as the emergency call, and the call information (Call-Info) provided with an approval identifier stored in the storage unit 306 is received. Send along with the message. The call information means that the emergency call before the call interruption is connected to the call processing terminal B (133).

When the UE 110 re-sends an emergency call including the call information, the E-CSCF 123 associates the request URI with the call processing terminal B 133 so that the re-routed emergency call can be connected to the call processing terminal B 133 again. To send an invite message. The method of reconnecting the emergency call will be described in detail with reference to FIG. 4.

4 is a flowchart illustrating a call processing method when an emergency call is interrupted in an IMS network according to an embodiment of the present invention.

In step 401, it is assumed that an emergency call originated by the UE 110 is connected to a call processing terminal. Thereafter, in step 403, the UE 110 stores an approval identifier indicating a call processing terminal for processing the emergency call in a storage unit. If the busy call is interrupted in step 405, the UE 110 transmits a new emergency call by transmitting a call request message including the grant identifier to the same request URI as the interrupted emergency call in step 407.

In step 409, the E-CSCF 123 receives an invite message including the grant identifier in call information from the UE 110 through an IMS network, and in step 411, the E-CSCF 123 receives the grant identifier. The call request message is transmitted by changing the request URI to the approval identifier included in the call information so that the new emergency call can be connected to the call processing terminal (call processing terminal B 133) connected before the call interruption.

If it is possible to connect the call processing terminal B 133 and the new emergency call in step 413, the process proceeds to step 415 and the new emergency call is reconnected with the call processing terminal (call processing terminal B 133) connected before the call is interrupted. do.

If the call processing terminal (call processing terminal B 133) connected before the call is interrupted or cannot be connected with the re-emergency emergency call, such as when there is no answer, it is the same as processing a normal emergency call. That is, in step 417, the EC 131 connects the new emergency call to another call processing terminal selected according to a random method or a cyclic method.

In the following detailed description of FIG. 5 and FIG. 6, a process of call processing in the IMS network will be described in detail.

5A and 5B are call processing diagrams illustrating a call processing method when an emergency call is interrupted in an IMS network according to an embodiment of the present invention.

An emergency call is connected between the UE 110 and the call processing terminal B 133 through steps 501 to 503. Steps 501 to 503 are the same as those of steps 201 and 203 of FIG. 2, and thus a detailed description thereof will be omitted. Only in step 503- (4), the UE 110 stores the grant identifier included in the call grant message received from the call processing terminal B 133 so that it can be used when the emergency call is interrupted.

In step 505, the emergency call is connected to the call processing terminal B 133 and is stopped for some reason.

In step 507, the control unit 308 of the UE 110 sends a second emergency call with the same request URI as the interrupted emergency call, and receives call information including the authorization identifier stored in step 503- (4). Send it in a message. That is, in step 507- (1), the UE 110 sends a request URI [Request-URI: sos@ims.com] and the call information [Call-Info: <sip: line_B@ims.com] to send an emergency call. The invite message including>] is transmitted to the P-CSCF 121.

As described above, the request URI [Request-URI: sos@ims.com] means that the arrival point of the call originated by the UE 110 is the PSAP 130, and the call information [Call-Info: <sip: line_B @ ims.com>] means the call processing terminal B 133 connected before stopping the emergency call.

In step 507- (2), the P-CSCF 121 forwards the invite message to the E-CSCF 123 because the call is an emergency call, and in step 507- (3), the E-CSCF 123 The invite message is transmitted to the call processing terminal B 133 according to the call information. That is, since the call information is included in the invite message, the E-CSCF 123 may directly transfer the invite message to the call processing terminal B 133 without transmitting the invite message to the EC 131.

In step 509, the call processing terminal B 133 transmits a call permission message (eg, 183 Session Progress) to the UE 110 through the reverse path of step 507 in response to the invite message. ) And the call processing terminal B 133 may initiate a call of a new emergency call. In this case, the new emergency call is reconnected with the call processing terminal B 133 before stopping the call so that the continuity of the emergency call can be maintained.

6A and 6B are call processing diagrams illustrating a call processing method when an emergency call is interrupted in an IMS network according to another embodiment of the present invention.

An emergency call is connected between the UE 110 and the call processing terminal B 133 through steps 601 to 603. Since the steps 601 to 603 are the same as the steps 501 to 503 of FIG. 5, a detailed description thereof will be omitted. In step 605, the emergency call is interrupted for some reason. Accordingly, an invite message is transmitted from the UE 110 to the call processing terminal B 133 in step 607. The invite message includes call information for requesting call processing terminal B 133 to reconnect an emergency call.

When the call processing terminal B 133 is in a call with another UE 110, the call processing terminal B 133 transmits a busy message (for example, 486 Busy) to the E-CSCF 123 in step 609. Alternatively, step 609 may be a case in which there is no response from the call processing terminal B 133 for a predetermined time. That is, the emergency call originated by the UE 110 cannot be connected to the call processing terminal B 133.

In step 611, the E-CSCF 123 processes the emergency call like a normal emergency call since the emergency call newly transmitted by the UE 110 may not be connected with the call processing terminal B 133. That is, in step 611-(1), the E-CSCF 123 transmits the invite message to the EC 131, and the EC 131 transfers the invite message to the call processing terminal C 134. . The selection of the call processing terminal C 134 is a result selected by the random method or the cyclic method as in the normal emergency call processing.

In step 613, the call processing terminal C 134 transmits a call permission message to the UE 110 in response to the invite message received in step 611 to process the call of the emergency call re-sent by the UE 110. It is connected to the terminal C (134).

That is, if the call processing terminal which handled the emergency call before the interruption of the call cannot handle the newly sent emergency call after the interruption of the call, the newly transmitted emergency call is processed in the same way as the normal emergency call process. You can respond quickly.

Although the present invention has been described in detail so far, it should be apparent that the embodiments mentioned in the process are only illustrative, and not restrictive, and the present invention is provided by the following claims. Within the scope not departing from the scope of the present invention, component changes to the extent that they can be equivalently substituted from the present invention will fall within the scope of the present invention.

According to the technical configuration of the present invention, when the emergency call is interrupted while the emergency call is connected to the call processing terminal in the IMS network, the newly transmitted emergency call may be connected to the call processing terminal again. I can keep it. Therefore, prompt action can be taken for emergency situations.

Claims (6)

In the call processing method of emergency call through IP Multimedia Subsystem (IMS) network, When the first emergency call originated by the user terminal is connected to the first call processing terminal selected by a preset method among a plurality of call processing terminals in the emergency call processing center, the user terminal may identify an approval identifier indicating the first call processing terminal. Receiving and storing; Transmitting, by the user terminal, a call request message including the stored grant identifier to the IMS network to send a second emergency call to the same request URI as the first emergency call after the first emergency call is stopped; And And the second emergency call is connected to the first call processing terminal by using the approval identifier. The method of claim 1, And when the second emergency call cannot be connected with the first call processing terminal, connecting the second emergency call with another call processing terminal in the emergency call processing center. An emergency call processing apparatus in a user terminal for transmitting and receiving a message through an IP multimedia subsystem (IMS) network, An external interface unit for transmitting and receiving a signal with the IMS network; A data processor which modulates and demodulates a signal transmitted and received through the external interface; Send a first emergency call, and when the first emergency call is connected with a first call processing terminal in an emergency call processing center, receives a call admission message including an approval identifier indicating the first call processing terminal, and receives the first emergency call. A control unit which transmits a second emergency call to the same request URI as the first emergency call after the call is interrupted and transmits a call request message including the approval identifier; And, Emergency call processing device comprising a storage unit for storing the approval identifier. In a call processing system for processing an emergency call, including an IP Multimedia Subsystem (IMS) network, An emergency call processing center having a plurality of call processing terminals connected to the IMS network to process the emergency call; And Transmitting a first emergency call with a first call processing terminal selected by a preset method among the plurality of call processing terminals, receiving and storing an approval identifier indicating the first call processing terminal through the IMS network, and And a user terminal which transmits a second emergency call to the same request URI as the first emergency call after the first emergency call is interrupted, and transmits a call request message including the stored authorization identifier to the IMS network. The method of claim 4, wherein The IMS network further includes an emergency call session control function that receives the call request message requesting the second emergency call and delivers the call request message to the first call processing terminal according to the approval identifier. . The method of claim 5, And the emergency call session control function is further configured to transmit the call request message to the emergency call processing center when the second emergency call cannot be connected with the first call processing terminal.

Images