KR20060131231A - Method and system for providing a conference call during push-to-talk - Google Patents

Abstract

The present invention provides a push-to-talk (PTT) communication between a plurality of terminals operating as clients in a mobile communication network including a push-to-talk over cellular (PoC) server, a multi-party server, and a mixer for mixing for multi-party calls. A providing method comprising: performing a request procedure for switching to a conference call during a PoC session between terminals; Performing a conference client invitation / participation procedure to open the conference session through the conference server; And performing a procedure for releasing the conference call session between the PoC server and the terminal. In addition, the present invention can terminate the existing PoC session without newly initiating the multi-party call service, and can switch to the multi-party call during the PTT service, and switch to bidirectional communication between all or some participants during the PoC session, which is a one-way communication method. This is possible.

Description

METHOD AND SYSTEM FOR PROVIDING PTT TO CONFERENCE}

1 is a conceptual diagram of a PTT service network for a general PTT service

2 is a block diagram of a PMA service network based on OMA

3 is a diagram illustrating a call setup process of an IMS-based PTT service

4 is a block diagram of an IMS-based PTT service network

5a and 5b are diagrams illustrating a call setup process of an IMS-based PTT service network

Figure 6 is a network configuration capable of PTT vs. multi-party call in accordance with a preferred embodiment of the present invention

7 illustrates a PTT to conference call scenario according to a preferred embodiment of the present invention.

8A and 8B illustrate a call setup process according to the scenario of FIG. 7 in accordance with a preferred embodiment of the present invention.

9 is a block diagram of a terminal capable of performing a PTT versus a conference according to a preferred embodiment of the present invention.

The present invention relates to a method and a system for providing a Push to talk over Cellular (PoC) service in a cellular network, and more particularly, to a method and a system for providing a PTT-to-conference service.

Push To Talk (hereinafter referred to as "PTT") service is an instant messenger service such as a kind of radio service. As the word means, it is possible to provide a very fast communication service compared to the waiting time of the general terminal because the simple communication can be performed immediately by pressing the switch and talking. The convenience can be doubled because the PTT immediately shows whether the other party can receive on the terminal screen. PTT service is able to communicate immediately without unnecessary processes such as dialing or ringing tone, so the biggest advantage is that the PTT service is connected immediately and at high speed compared to the call waiting time of general mobile communication.

PTT service with these advantages includes one-way voice broadcasting, packetized voice over wireless data, personal and group messaging support, instant access, and simple user interface.

Push to talk over cellular (PTT) on cellular is a PTT service function implemented on an existing cellular terminal or PCS terminal. Currently, standards for PTT service are in progress centering on Open Mobile Alliance (OMA), and PTT service based on IP Multimedia Subsystem (hereinafter referred to as "IMS") in 3rd Generation Partnership Project (3GPP). I'm working on it.

1 is a conceptual diagram of a PTT service network for a general PTT service.

Referring to FIG. 1, the talker 101, one of the members of the group, performs PTT instant communication through the wireless network 109 to the talker subgroups 101, 103, 105, and 107. The situation is shown. When the talker 101 presses the switch and speaks a simple intention, the talker subgroup consisting of at least one talker receives the talker 101's voice. The talker 101 of such a general PTT service is limited to one person and may designate at least one talker group in advance and express a voice by voice, such as a kind of radio communication.

2 is a diagram illustrating an OMA-based PTT service network.

Referring to FIG. 2, the OMA-based PTT service network includes a user agent (UE) 200, an XML Document Management Server (XDMS) 212, and a presence server (Presence Sever) ( 208, a PoC server 201 including a SIP proxy 206 and a packet processor 202.

The UE 200 is a terminal device capable of PTT service, the XDMS 212 is a server that manages a document in XML format, the presence server 208 and the SIP proxy 206 is defined in the SIP standard document It is an entity that mediates a PTT service by playing a role, and the PoC server 201 is a server that enables a PTT service in a cellular network.

Here, the functions of the interfaces of the entities constituting the OMA based PTT service network are as follows. The UE-XDMS interface 210 is an interface for inquiring / receiving information on a group list and a policy through the access network 211. The XDMS-PoC server interface 213 is an interface for inquiring / receiving information on the group list and the policy for the PoC service. The XDMS-Presence Server Interface 209 is an interface for inquiring / receiving information on a policy for the presence service.

In addition, the SIP proxy-presence server interface 207 has a connection standard between the SIP proxy and the presence server based on SIP, and is used to register / store / delete / view user's participation information. The UE-SIP proxy interface 204 supports SIP as an interface for transmitting signaling for a Poc session between the PoC client and the Poc server through the access network 211, provides PoC client registration, and provides authentication / Perform permissions. The UE-PoC server interface 203 is used for media transmission and talk burst control and RTP / RTCP (Real-time Transport Protocol / RTP Control Protocol) is used. The SIP proxy-PoC server interface 205 supports SIP as an interface for transmitting signaling for a PoC session between a PoC client and a PoC server, and is also used for charging and the like.

3 is a diagram illustrating a call setup process of an IMS-based PTT service.

Referring to FIG. 3, the OMA-based PTT service is largely a PoC Client A Home & Controlling Network 420 and a PoC Client B Home Network 430. It can be distinguished by call flow between. The PoC Client A Home & Controlling Network 420 is a PoC Client A 421, a SIP / IP Core (A) 422, and a PoC Server (A) (participating & controlling) ( 423). In addition, the PoC Client B Home Network 430 includes a PoC server (participating) 431, a SIP / IP core (B) 432, and a PoC Client B 430. do.

In step 301, the PoC client A 421 initiates an ad-hoc PoC group session or 1-1 PoC session by transmitting an INVITE message to the SIP / IP core (A) 422. In step 302, the SIP / IP core (A) 422 is a PoC server (participating & controlling) 423 based on the PoC client and the PoC user's Inviting PoC Address on the PoC service indication. Route the INVITE message.

In step 303, the PoC server (participating & controlling) 423 transmits an INVITE message to the SIP / IP core (A) 422. In step 304, the SIP / IP core (A) 422 routes the INVITE message to the SIP / IP core (B) 432. In step 305, the SIP / IP core (B) 432 sends the INVITE to the PoC server (participating) 431 based on the PoC address of the Invited PoC Client and the PoC service indication. Route the message.

In step 306, when the PoC client B 433 automatically accepts the session, the PoC server B (participating) 432 transmits an AUTO- ANSWER message to the SIP / IP core (B). In step 307, the SIP / IP core (B) 432 transmits the AUTO-ANSWER message to the SIP / IP core (A).

In step 308a, the SIP / IP core (A) 422 transmits the AUTO-ANSWER message to the PoC server (A) 423. In step 308b, the PoC server (participating) 431 transmits an INVITE message requesting the PoC session establishment to the SIP / IP core (432).

When receiving the AUTO-ANSWER message in step 309a, the PoC server (A) (participating & controlling) 423 transmits an UNCONFORMED OK message to the PoC client. In step 309b, the SIP / IP core (B) 432 routes the INVITE message to the PoC client B.

In step 310a, the SIP / IP core (A) 422 delivers the UNCONFORMED OK to the PoC client A (421). In step 310b, when the PoC client B 433 receives the INVITE message, the PoC client B 433 transmits an OK message for the INVITE message.

In step 311a, the PoC server (participating & controlling) 423 transmits a talk burst confirmation message to the PoC client A 421. In step 311b, the SIP / IP core (B) 432 forwards the OK message to the PoC server (B) (participating) 431.

In step 312a, the PoC server (A) 421 transmits media to the PoC server (A) (participating & controlling) 423. In step 312b, the PoC server (participating) 431 receives an OK message. In step 313b, the SIP / IP core (B) 432 receives an OK message from the PoC server (participating) 422. In step 314b, the SIP / IP core (A) 422 transmits the OK message to the PoC server (A) (participating & controlling) 423.

In step 315, the PoC server (A) 422 transmits the received talk burst indication to the PoC server (B) 431. In step 316, the PoC server (participating) 431 relays the received talk burst message to the PoC client B 433.

4 is a configuration diagram of an IMS-based PTT service network.

Referring to FIG. 4, the IMS-based PTT service network includes a UE 400, an XML Document Management Server (XDMS) 415, a presence server 419, a PoC server 417, and a P-CSCF. An IMS core 401 including a Proxy-Call Session Control Function (411) and a Serving-Call Session Control Function (S-CSCF) 413.

The UE 400 operates as a PTT client. In order to receive the PTT service, the UE 400 transmits a SIP signaling message to the PoC server 417 to be allocated a media channel. When the PoC session is established, the UE 400 transmits and receives a packet through a bearer channel established between the PoC server 417 and the UE 400.

The PoC server 417 is responsible for signaling and bearer processing for the PTT service. The SIP message transmitted from the UE 400 is processed to establish a media channel (RTP) between the UE 400 and a PoC server (packet processor) 417. When the media session is established, the PoC server 417 copies and distributes packets for packet transmission to the UE 400. In addition, the PoC server 417 performs the flow control (floor control) during the PTT service, and generates the relevant data for billing and performs the function of reporting it to the billing server.

The XDMS 415 is a server that manages an XML document, and the presence server 208 is an entity that mediates a PTT service by performing a role defined in a SIP standard document, and the P-CSCF 411. And the S-CSCF 413 is an entity that performs call switching in the IMS network.

The UE- (P-CSCF) interface Gm supports SIP as an interface for communication (processing related to registration and session control) between the UE 300 and the IMS core 310. The (P-CSCF)-(S-CSCF) interface (Mw) serves to perform signaling message transfer as an interface for communication between CSCFs and supports SIP. The (S-CSCF)-(Presence Server) interface (ISC) is an interface between the CSCF and the presence server, which is a SIP application server, used to provide presence services through the IMS core 310. The UE-XDMS interface Ut is an interface through which the UE 300 manages (creates / deletes / views) information related to a service in the XDMS 313 (group list and policy information).

5A and 5B are diagrams illustrating a call setup process of an IMS-based PTT service network.

5A and 5B, a network A and a PoC server (B) including a UE-A 530, a PS domain A 535, an IMS core (A) 540, and a PoC server (A) 545. 550, IMS core (B) 555, PS domain B (560) and UE-B (565) network B is divided into large.

In step 501, the user A of the UE-A 530 presses a PTT indication / button on a terminal instructing communication with the user B of the UE-B 565. In step 502, the UE-A 530 creates an SIP session for the PoC communication with the UE-B 565 as the destination address by sending an INVITE message to the IMS core (A) 540. In steps 503 to 504, the IMS core (A) 540 identifies the service indication and routes the INVITE message to the PoC server (A) 545.

In steps 505 to 506, the PoC server (A) 550 together with the IMS core (A) 540 delivers an INVITE message toward the IMS Core B 555. In steps 507-508, the IMS core (B) 555 identifies the service indication and routes the INVITE message to the PoC server (B) 550. In step 509a, the UE-B 565 automatically sends the AUTO-ANSWER to the PoC server (A) 545 by accepting the session.

In step 509b, the PoC server (B) 550 delivers an INVITE message to the UE-B 565 via the IMS core (B) 555. In steps 510a to 511a, the IMS core (B) 555 forwards the AUTO-ANSWER message to the PoC server (A) 545 via the IMS core (A) 540.

In steps 512a to 513a, the PoC server (A) 545 transmits 200 OK toward the UE-A 530 based on the AUTO-ANSWER where the PoC server (A) 545 supports media buffering, At the same time, a talk burst confirm message is transmitted to the UE-A 530. In step 514a, when a service based local policy is applied to the network of UE-A 530, IMS Core (A) 540 generates an authorization token for the session, and firstly an available and trusted SIP response. The authority token is inserted into the message and transmitted to the UE-A 530.

In steps 517a to 518a, after the UE-A 530 receives both the 200 OK and the talk burst confirmation message, the UE-A 530 may transmit the media data to the PoC server (A) 545. Do. In step 519a, the IMS core (A) 540 sends an ACK to the PoC server (A) 545. In step 520a, the PoC server (A) 545 is sent from the UE-B 565. Buffer the received media until receiving a positive response. UE-A 530 continues to transmit the media.

In steps 510b to 515b, in the case of a service-based area policy applied in the network to which the UE-B 565 belongs, the IMS core (B) 555 generates a permission token for the session, and the permission in the INVITE message. Insert the token and pass it to UE-B 565.

Typically UE-B needs to be paged before the INVITE message is translated. The INVITE message is delivered to the PS domain without any functional change.

In steps 513b to 514b, after receiving the INVITE message, the UE-B 565 accepts the session by returning 200 OK. UE-B 565 is capable of additional settings (traffic class streaming and bandwidth for negotiable media parameters) for media and talk burst control exchanging IP addresses and APNs.

In steps 515b to 518b, the IMS core (B) 555 delivers the 200 OK to the PoC server (B) 550, and the IMS core (B) 556 and the IMS core (A) 540. The 200 OK is forwarded to the PoC server (A) 545 via.

In steps 521 to 523, the PoC server (A) 545 transmits an ACK for the session establishment, and the ACK passes through an IMS core (A) 540 and an IMS core (B) 555 to the PoC. Forwarded to server (B) 550. The PoC server (B) 550 sends an ACK for the session.

In steps 524 to 525, the PoC server (B) 550 sends an ACK for the session to the UE-B 565 via an IMS core (B) 555. The media buffered from the UE-A 530 to the PoC server (A) 545 is transmitted from the PoC server (A) to the PoC server (B). PoC server (B) 550 sends media to UE-B 565.

In the PTT service according to the related art operating as described above, only a user who has a voice can make a call, and other users can only sign a call. That is, the PTT service is a one-way communication, and there is a limitation that several people can't make a phone call at the same time.

Accordingly, an object of the present invention is to provide a method and apparatus that enables users of a PTT service to switch to a conferencing service during a PTT service at the request of a user.

A method of an embodiment of the present invention for achieving the above object, as a client in a mobile communication network having a push-to-talk over cellular (PoC) server, a conference server and a mixer for mixing for the conference A method for providing a conference call during a push-to-talk (PTT) process between a plurality of terminals, the method comprising: performing a request procedure for switching to a conference call during a PoC session between the terminals; Performing a conference client invitation / participation procedure to open the conference session through the conference server; And performing a procedure for releasing the conference call session between the PoC server and the terminal.

In addition, the system of the embodiment of the present invention, in a system for providing a multi-party call during push-to-talk (PTT) progress between a plurality of clients through a mobile communication network, signaling and bearer processing for the PTT service, and multi-way during PTT A PoC server that performs bearer setup between the conference client and the mixer for signaling for call transfer and media processing for conferences; A conferencing server that handles signaling for the conferencing and interacts with a mixer to allocate media channels for clients; A mixer that performs a media mixing function for a multiparty call service and allocates media resources to a client; And a terminal operating as the client.

In addition, the terminal of the embodiment of the present invention, in a terminal equipped with a client for providing a multi-party call during the push-to-talk (PTT) through the mobile communication network, the client centered on the main control (main control) task in the real-time operating system PTT service unit to process the function of; And components on a physical layer and a media access control layer to communicate with the PTT service unit.

Hereinafter, with reference to the accompanying drawings will be described in detail the operating principle of the preferred embodiment of the present invention. Like reference numerals refer to the same elements as shown in the drawings, even though they may be shown on different drawings, and in the following description, detailed descriptions of related well-known functions or constructions are unnecessary. If it is determined that it can be blurred, 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 case of a PTT service for a group, that is, one person can speak to a terminal by using several terminals, and it can be said to overcome the limitation of one-to-one communication that a telephone has. Small and medium-sized groups can be designated and talked, and one-to-one wireless calls are, of course, possible. In order to switch to the conference service during the service is configured as follows.

Figure 6 is a network configuration capable of PTT vs. multi-party call according to a preferred embodiment of the present invention.

Referring to FIG. 6, a UE 600, a PoC server 610, a conference server 620, a mixer 630, and a SIP / IP core (IMS) 640 are included.

The UE 600 operates as a PTT client. The UE 600 performs a function of transmitting SIP signaling for switching to the PoC server 610 in order to switch the PTT service to the conference call service during the PoC session. In addition, in the case of the PTT service, the PoC server 610 and the mixer 630 and the bearer channel are set in the case of the multi-call service, and the packet is transmitted and received through the configured bearer channel.

The PoC server 610 is responsible for signaling and bearer processing for the PTT service. It also handles signaling for PTT versus conference. When the PoC server 610 receives a SIP message for PTT to conference switching from the UE 600, the PoC server 610 transmits a SIP message including media information about the participants to the related conference server. It also performs the function of generating relevant data for billing and reporting it to the billing server. The PoC server 610 is responsible for controlling the conference, and the PoC server (conference control logic) 610 performs bearer setup between the conference participant and the mixer for media processing (mix or bridge) for the conference. do.

The conference server 620 is responsible for signaling processing for the conference service. When the conference server 620 receives a SIP message from the PoC server including media information about all participants participating in the PoC session, the conference server 620 uses the received media information to establish a conference call with each participant. Set it. The conference server 620 interoperates with the mixer using the H.248 / Megaco protocol to allocate media channels for the participants. In addition, the multi-party server 620 generates a relevant data for billing and reports the data to the billing server.

The mixer 630 performs a media mixing function for the conference call service. In addition, the mixer 630 allocates a media resource to the UE 600 through the H.248 / Megaco interworking with the multiparty server 620. After the PoC session is established, at the request of the PTT participant, the PoC server 610 converts the PoC session into a conference call session. The following is a scenario of PTT-to-MFP conversion.

7 is a diagram illustrating a PTT to multi-party call switching scenario according to a preferred embodiment of the present invention.

Referring to FIG. 7, the PTT-to-conference switching scenario includes a PoC server 710 including a conference server 700, a media relay server (MRS) 720, a mixer 730, and a plurality of UEs. 740, 750, and 760, a request procedure for PTT-to-conference, invite / join a conference participant to open a conference session, and a procedure for disconnecting an existing PoC session of a PoC server.

-Perform the request procedure for PTT to conference

In step 701, the UE1 740 transmits a SIP message (PTT to conference call indication) for PTT to conference call conversion to the PoC server 710. In step 702, the PoC server 710 transmits a conference call initialization message to the conference server 700. At this time, the PoC server 710 transmits the location (URI) and media information (RTP port, codec, etc.) for the participants used during the corresponding PoC session to the conference server 700. At this time, the PoC server 710 notifies each PTT client by using the announcement or the like that the PoC session is converted to a conference call. In step 703, the conference server 700 transmits the media information received from the PoC server 710 to the mixer 730 that performs the mixing for the conference, and the mixer 730 uses the information to participate in the conference. Allocate media for.

 -Invite / join a conference participant to open the conference

In step 704, the conference server 700 sends a conference invitation message (including media information assigned in the mixer) to each participant to establish a conference session. In step 705, after the invitation / participation to each participant is completed, the conference server 700 notifies the PoC server 710 that the conference session is completed. At this time, the conference server 700 informs the participants that the conference is set up by using the announcement or the like.

-PoC server performs the procedure to terminate the existing PoC session

In step 706, after being informed that the conference setting is completed from the conference server 700, the PoC server 710 performs a PoC session release procedure for disconnecting an existing PoC session.

8A and 8B illustrate a call setup process according to the scenario of FIG. 7 according to a preferred embodiment of the present invention.

8A and 8B, in step 801, from the state in which the RTP bearer channel for the PoC service is formed, the UE-A 850 sends a REFER for PoC to the conference to the SIP / IP core (A) 855. Send a message. In step 802, the SIP / IP core (A) 855 forwards the REFER message to the PoC server (A) 860. In step 803, the PoC server (A) 860 sends an Accepted message to the SIP / IP core (A) 855. In step 804, the SIP / IP core (A) 855 transmits an Accepted message to the UE-A 850.

In steps 805 to 808, the PoC server (A) 860 sends a NOTIFY message to the UE-A 850 via the SIP / IP core (A) 855 and receives an OK message.

In steps 809a to 809c, the PoC server A sends out an announcement broadcast notifying that it is switching to the multi-call service. In step 810, the PoC server (A) sends an INVITE message to the SIP / IP core (A) 855. In step 811, the SIP / IP core (A) 855 sends an INVITE message to the conference server 865. In steps 812 to 813, the conference server 865 sends an ADD message to the mixer 870 and receives an OK message.

In steps 814 to 817, the conference server 865 sends an INVITE message via the SIP / IP core (A) 855 and receives an OK message. In step 818, the conference server 865 sends an INVITE message to the SIP / IP core (A) 855. In steps 819 to 822, the SIP / IP core (A) 855 transmits an INVITE message to the UE-B 885 via the SIP / IP core (B) 880 and receives an OK message. In steps 823 to 825, the SIP / IP core (A) 855 transmits and receives an OK message to the conference server 865 and transmits an OK message to the PoC server (A) again. Thereafter, an RTP session is established for the conference service.

In steps 826 to 829, the PoC server (A) 860 sends a NOTIFY message to the UE-A 850 via the SIP / IP core (A) 855 and receives an OK message. At this time, the mixer 870 transmits a guide broadcast to notify the start of the conference. In steps 831 to 834, the PoC server (A) 860 sends a BYE message to the UE-A 850 via the SIP / IP core (A) 855 and receives an OK message.

In steps 835 to 838, the PoC server (A) 860 sends a BYE message to the PoC server (B) 875 via the SIP / IP core (B) 880 and receives an OK message. In steps 839 to 842, the PoC server (B) 875 transmits a BYE message via the SIP / IP core (B) 880 and receives the OK message to release the PoC session.

9 is a block diagram of a terminal capable of performing PTT versus conference according to a preferred embodiment of the present invention.

Referring to FIG. 9, the terminal includes a PTT service unit 900, a modem 910, a codec 920, a BBA 930, and an RF processor 940. The PTT service unit 900 software-processes the PTT-to-conference call function described in FIGS. 6 to 7 based on a main control task in a real-time operating system.

In addition, the modem 910, the codec 920, the BBA 930, and the RF processing unit 940 follow a communication procedure of a general terminal, and introduce only their characteristic functions as follows. The modem 910 handles protocols defined in standards such as IS-95A. The codec 920 generally employs 8 kbps Enhanced Variable Rate Codec (EVRC) from 8 kbps Qualcomm Code Excited Linear Prediction (QCELP). The baseband analog (BBA) 930 is composed of an integrated circuit and includes a second intermediate frequency processor, a second intermediate frequency processor, an analog to digital (A / D), or a digital to analog (D / A) converter. This is included. Analog to Digital (A / D) or Digital to Analog (D / A) converters are included. The RF processor 940 processes high and intermediate frequencies.

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.

In the present invention operating as described in detail above, the effects obtained by the representative ones of the disclosed inventions will be briefly described as follows.

The present invention has the effect of switching to a conference call during the PTT service without initializing the conference service newly after terminating the existing PoC session.

In addition, the present invention has the effect that it is possible to switch to two-way communication between all or some participants during the PoC session, which is a one-way communication method.

Claims (12)

A method for providing a conference call during a push-to-talk (PTT) process between a plurality of terminals operating as clients in a mobile communication network having a push-to-talk over cellular (PoC) server, a conference server, and a mixer for mixing for conferences. In Performing a request procedure for switching to a conference call during a PoC session between the terminals; Performing a conference client invitation / participation procedure to open the conference session through the conference server; And And performing a procedure for releasing the conference call session between the PoC server and the terminal. The method of claim 1, The process of performing a request procedure for switching to a conference call during the PoC session between the terminals, Transmitting, by the terminal wishing for the conference among the terminals, a conference call switching instruction message to the PoC server; Sending, by the PoC server, a conference call initialization message to the conference server; And  And the conference server transmits the media information received from the PoC server to the mixer, and the mixer allocates media for the conference client using the media information. The method of claim 2, wherein the PoC server transmits a location (URI) and media information about clients used during the PoC session to the conference server when the conference session initiation message is transmitted to the conference server. Said method. The method of claim 3, The media information includes a Real-time Transport Protocol (RTP) port and a codec. The method of claim 2, And the PoC server sends location and media information about clients used during the PoC session to the conference server and notifies each of the clients that the PoC session is switched to the conference. The method of claim 1, In the process of performing a conference client invitation / participation procedure to open the conference session through the conference server, The conference server sending a conference invitation message including media information assigned in the mixer to each of the clients to establish a conference session; And And the conferencing server notifies the PoC server that the conferencing session is complete. The method of claim 6, Wherein the conference server notifies the PoC server that the conference session is complete, and then notifies the plurality of clients that the conference has been established. The method of claim 1, The performing of the procedure for releasing the conference session may include the PoC server releasing the PoC session after receiving notification from the conference server that the conference setting is completed. In a system for providing a conference call during a push-to-talk (PTT) process between a plurality of clients through a mobile communication network, A PoC server that performs bearer setup between the conference client and the mixer for signaling and bearer processing for the PTT service, signaling for switching between conferences during the PTT, and media processing for the conference; A conferencing server that handles signaling for the conferencing and interacts with a mixer to allocate media channels for clients; A mixer that performs a media mixing function for a multiparty call service and allocates media resources to a client; And The system, characterized in that it comprises a terminal operating as a PTT client. The method of claim 9, The PoC server includes a function for generating and reporting related data for charging. The method of claim 9, The conference server includes the function of generating and reporting related data for billing. In a terminal equipped with a client that provides a conference call during push-to-talk (PTT) through a mobile communication network, A PTT service unit processing a function of the client based on a main control task in a real-time operating system; And And the components on the physical layer and the media access control layer to communicate with the PTT service unit.

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