KR20080079020A - Method and system for providing push to talk service in a communication system - Google Patents

Abstract

A method and a system for providing push to talk service in a communication system are provided to allow a specific terminal which speaks in the current session to obtain information on a terminal which is not able to listen to the speaking of the specific terminal. A specific terminal transmits a message for requesting information on terminals participating in the current session to a server which provides push to talk service to the specific terminal(313). The specific terminal receives information on a terminal which is not able to receive an RTP(Real-time Transport Protocol) message among the terminals participating in the current session from the server.

Description

METHOD AND SYSTEM FOR PROVIDING PUSH TO TALK SERVICE IN A COMMUNICATION SYSTEM}

1 is a diagram illustrating a procedure in which a server transmits an RTP message to terminals other than a terminal in a hold state in a general PoC communication system;

2 is a view schematically showing the structure of a PoC communication system;

3 is a diagram illustrating a procedure in which a server transmits an RTP message to terminals other than a terminal in a hold state in a PoC communication system according to an exemplary embodiment of the present invention.

The present invention relates to a communication system, and more particularly, to a method and a system for providing Push To Talk (PTT) service.

In the next generation communication system, due to the revolutionary development of mobile communication and the expansion of the communication network, more expanded and various services and applications using a terminal are provided. In addition, according to various needs of the user, the current terminal is expanding to a location service, a multimedia service, a PTT service, etc., instead of a simple call service. In particular, the PTT service supports various additional functions such as instant messenger and status display as well as group calls and voice calls, which have been possible in the conventional radio or trunked radio system (TRS).

Meanwhile, the PTT service has been actively standardized for Push-to-Talk over Cellular (PoC) service which is serviced in a mobile communication network. One feature that distinguishes the PoC service from the existing mobile communication service is that a user may make a call while moving among sessions belonging to a plurality of sessions. The requirement for users to be able to make calls over multiple sessions is specified in the requirements of the Open Mobile Alliance (OMA), an organization that defines mobile communications services. It is.

In addition, the PTT service based on the PoC network is a unidirectional service in which only a terminal having a voice, that is, a data transmission opportunity, can transmit data among session participant terminals. In other words, when any one of the session participant terminals requests a talk right to the server to obtain a talk right, the server grants a talk right to the terminal requesting the talk right, and the terminal having the talk right proceeds.

Here, the server can listen to the speech of any one terminal, i.e., can receive data of any one terminal when giving the right to speak, that is, a data transmission opportunity, to any one terminal requesting the speaking right. The count information of the terminal is transmitted. Accordingly, any one terminal that has received the number information of the terminal together with obtaining the data transmission opportunity can know the number of terminals that can receive their own data.

Then, in the general PoC communication system with reference to FIG. 1, the server cannot receive a real-time transport protocol (RTP) message in a general PoC communication system, for example, a hold_on state. A procedure for transmitting the RTP message to the remaining terminals except for the terminal of the will be described.

1 is a diagram illustrating a procedure in which a server transmits an RTP message to terminals other than a terminal in a hold-on state in a general PoC communication system.

Referring to FIG. 1, the PoC communication system includes an Internet Protocol Multimedia Subsystem (IMS) server 103, a PoC server 105, and a media server 107. ), And terminals currently participating in a session, for example, a first terminal 101, a second terminal 109, and a third terminal 111.

First, the first terminal 101 transmits to the IMS server 103 a SUBSCRIBE (SUBSCRIBE, hereinafter referred to as SUBSCRIBE) message requesting the information of the terminals participating in the current session (step 113). The IMS server 103 transmits the SUBSCRIBE message to the PoC server 105 (step 115). The PoC server 105 transmits a 200 OK message to the IMS server 103 confirming receipt of the SUBSCRIBE message (step 117), and the IMS server 103 sends the 200 OK message to the first terminal 101. Transmit (step 119).

Upon receiving the SUBSCRIBE message, the PoC server 105 uses a notification (NOTIFY, hereinafter referred to as 'NOTIFY') message to manage a list of terminals, that is, a list of terminals participating in a current session. ) Is transmitted to the IMS server 103 (step 121), and the IMS server 103 transmits the NOTIFY message to the first terminal 101 (step 123). Here, the NOTIFY message transmits the new participant terminal information when a new terminal joins the current session, and transmits the withdrawn participant terminal information when any one of the terminals participating in the current session leaves the current session. do. Meanwhile, the first terminal 101 transmits a 200 OK message to the IMS server 103 confirming reception of the NOTIFY message (step 125), and the IMS server 103 sends the 200 OK message to a PoC server ( 105) (step 127).

At this time, the second terminal 109 in a state where it is impossible to receive an RTP message, for example, a hold_on state, may be referred to as a session description protocol (SDP) to express its state information. A new invitation message (refresh-INVITE, hereinafter referred to as 'refresh-INVITE') set to "a = sendonly" to the IMS server 103 (step 129). Here, the hold-on state terminal is a terminal that can not receive the RTP message but can transmit only. The IMS server 103 transmits the refresh-INVITE message to the PoC server 105 (step 131). The PoC server 105 transmits a 200 OK message to the IMS server 103 confirming reception of the refresh-INVITE message in step 129 (step 133), and the IMS server 103 sends the 200 OK message as a second message. The terminal transmits to the terminal 109 (step 135).

Then, the first terminal 101 among the terminals participating in the current session requests a talk burst request (TB_REQ: Talk Burst Request) to the media server 107 that controls the Real-time Transport Control Protocol (RTCP). In the following description, a TB_REQ message is transmitted (step 137). The media server 107 receiving the TB_REQ message transmits a talk burst grant (TB_GRANT: Talk Burst Granted) message to the first terminal 101 to grant a talk right (139). step). In addition, the media server 107 transmits a talk right take (TB_TAKEN: Talk Burst Taken, hereinafter 'TB_TAKEN') message indicating that the right to speak has been granted to the first terminal 101 in the current session. Except), it transmits to the terminals participating in the session, for example, the second terminal 109 and the third terminal 111 (steps 141 and 143).

The first terminal 101 having obtained the voice in the current session transmits an RTP message to the media server 107 (step 145), and the media server 107 transmits the RTP message to the third terminal 111. (Step 147).

As described above, the second terminal 109 among the terminals participating in the current session in the PoC communication system is a hold-on state terminal, and is a terminal capable of only receiving RTP messages but not transmitting them. If the first terminal 101 is a speaker terminal that speaks in the current session, the first terminal 101 does not know the state information of the second terminal 109 and thus speaks its own speech in the current session. There was a problem in that the listening terminal, that is, the terminal capable of receiving an RTP message transmitted by itself, is not known.

Therefore, there is a problem in that a smooth PTT service cannot be provided due to a problem of not correctly knowing information of a terminal receiving an RTP message transmitted by the speaker terminal in the current session.

Accordingly, an object of the present invention is to provide a method and system for providing a Push To Talk (PTT) service in a communication system.

Another object of the present invention is to provide a method and system for providing a PTT service for acquiring terminal information in a state in which a speaker terminal cannot hear his / her speech in a communication system.

The method of the present invention for achieving the above objects; In the method for providing a PTT service in a communication system, a specific terminal in a current session transmits an information request message of terminals participating in a current session to a server that provides a push-to-talk service to the terminal, and the current session from the server. Receiving information of a state terminal that is unable to receive a real-time transport protocol (RTP) message among the terminals participating in the.

Another method of the present invention for achieving the above objects is; In the method for providing a PTT service in a communication system, a server may receive an information request message of terminals participating in a current session from a specific terminal, and a real-time transport protocol (RTP) among terminals currently participating in a session. Protocol) obtaining information of the state terminal that is unable to receive a message, and transmitting information of the state terminal that cannot receive the RTP message to the corresponding terminal in response to the request message.

The system of the present invention for achieving the above objects; A system for providing a PTT service in a communication system, comprising: transmitting an information request message of terminals participating in a current session to a server providing a PTT service, and receiving a RTP message among terminals participating in a current session from the server; It includes a specific terminal for receiving information.

Another system of the present invention for achieving the above objects is; In the PTT service providing system in a communication system, receiving information request message of the terminals participating in the current session from a specific terminal, obtains information of the state terminal that can not receive the RTP message among the terminals participating in the current session, And a server for transmitting the information on the state terminal that is unable to receive the RTP message corresponding to the message.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, only parts necessary for understanding the operation of the present invention will be described, and other background art will be omitted so as not to distract from the gist of the present invention.

In the present invention, Push-To-Talk (PTT: Push-To-Talk) communication system is referred to as Push-to-talk over Cellular (PoC) communication system. We propose a method and system for providing a service. In particular, the present invention obtains information of a terminal, for example, a hold_on state terminal, in which a server cannot receive a real-time transport protocol (RTP) message in a current session. We propose a method and system for providing a PTT service.

In addition, in the present invention, for convenience of description, a service providing method and system will be described using an example of a PoC communication system, but the service providing method and system proposed by the present invention can be applied to all communication systems as well as the PoC communication system. Of course.

Next, a description will be given of the structure of the PoC communication system that is the basis of the PTT service with reference to FIG.

2 is a diagram schematically illustrating a structure of a PoC communication system.

Referring to FIG. 2, the PoC communication system will be referred to as a PoC client 201, an access network 203, and an internet protocol multimedia subsystem (IMS). Server 205, Group List Management Server (GLMS: hereinafter referred to as GLMS) 207, presence server 209, PoC server ( 210, a media server 211, and a remote PoC network 213.

The PoC client 201 transmits or receives a call message as a plurality of terminals participating in a session requesting a PTT service, and is connected to the IMS server 205 which is a SIP / IP multimedia support network through the access network 203. In addition, the PoC client 201 creates a new PoC session from the PoC user side or joins an already created session. In addition, the PoC client 201 generates and delivers a talk burst to the PoC server 210.

The IMS server 205 is connected to the PoC server 210, the GLMS 207, the presence server 209, etc. to support the PoC service and provides services to the terminals. The PoC server 210 manages a PTT session as a server providing a PTT service, and the PoC server 210 includes a media server 211. The media server 211 controls a Real-time Transport Control Protocol (RTCP) message and an RTP message.

The GLMS 207 stores information of terminals participating in the session, and transmits the stored terminal information to the PoC server 210 when the PoC server 210 requests the information of the terminals. The presence server 209 stores state information of terminals participating in the session.

Next, referring to FIG. 3, a procedure for transmitting an RTP message to other terminals except for a state terminal, for example, a hold-on state terminal, in which a server cannot receive an RTP message in a PoC communication system according to an embodiment of the present invention will be described. Shall be.

3 is a diagram illustrating a procedure in which a server transmits an RTP message to terminals other than a terminal in a hold state in a PoC communication system according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the PoC communication system includes an IMS server 303, a PoC server 305, a media server 307, a PoC client, for example, a first terminal 301 and a second terminal 309. And a third terminal 311.

First, the first terminal 301 transmits a subscribing message (SUBSCRIBE, hereinafter referred to as 'SUBSCRIBE') to the IMS server 303 to request information on terminals currently participating in the session (step 313). The IMS server 303 transmits the SUBSCRIBE message to the PoC server 305 (step 315). The PoC server 305 transmits a 200 OK message to the IMS server 303 confirming receipt of the SUBSCRIBE message (step 317), and the IMS server 303 sends the 200 OK message to the first terminal 301. Transmit (step 319).

Upon receiving the SUBSCRIBE message, the PoC server 305 uses a notification (NOTIFY, hereinafter referred to as 'NOTIFY') message to manage a terminal list, that is, a terminal list participating in the current session. ) Is transmitted to the IMS server 303 (step 321), and the IMS server 303 transmits a NOTIFY message including the terminal list to the first terminal 301 (step 323). Here, the NOTIFY message transmits new participant terminal information when a new terminal joins a current session, and transmits the withdrawn participant terminal information when any one of the terminals participating in the current session leaves the current session. . Meanwhile, the first terminal 301 transmits a 200 OK message confirming reception of the NOTIFY message to the IMS server 303 (step 325), and the IMS server 303 transmits the 200 OK message to a PoC server ( 305) (step 327).

At this time, the second terminal 109 in the hold-on state is set to "a = sendonly" in the Session Description Protocol (SDP) (hereinafter referred to as "SDP") to express its state information. The invitation (refresh-INVITE, hereinafter referred to as 'refresh-INVITE') message is transmitted to the IMS server 303 (step 329). In this case, the hold-on state is a terminal capable of not receiving RTP messages but only transmitting them. The IMS server 303 transmits the refresh-INVITE message to the PoC server 305 (step 331).

The PoC server 305 transmits a 200 OK message to the IMS server 303 confirming receipt of the refresh-INVITE message in step 329 (step 333), and the IMS server 303 sends the 200 OK message as a second message. The terminal transmits to the terminal 309 (step 335).

Meanwhile, the PoC server 305 receiving the refresh-INVITE message transmits a NOTIFY message including the state information of the second terminal 309 in the current session in step 313, that is, the first terminal (ie, the first terminal). 301 is transmitted to inform the second terminal 309 of the hold-on state. In other words, the PoC server 305 transmits a NOTIFY message including the state information of the second terminal 309, that is, the information indicating the hold-on state, to the IMS server 303 (step 337), and the IMS server 303 ) Transmits the NOTIFY message to the first terminal 301 (step 339). Accordingly, the first terminal 301 that receives the NOTIFY message and obtains information on the terminal that is unable to receive the RTP message in the current session, acquires the right to speak in the current session and proceeds to speak. The terminal which can receive this transmitted RTP message can be known.

Upon receiving the NOTIFY message, the first terminal 301 transmits a 200 OK message to the IMS server 303 confirming reception of the NOTIFY message in step 337 (step 341), and the IMS server 303 sends the 200 OK message. The message is transmitted to the PoC server 305 (step 343).

Then, the first terminal 301 that has obtained the information of the terminal that cannot receive the RTP message in the current session is called a talk burst request (TB_REQ: TB_REQ) to the media server 307 controlling the RTCP. In step 345, the message is transmitted. Upon receiving the TB_REQ message, the media server 307 transmits a talk right grant (TB_GRNT: Talk Burst Granted) message to the first terminal 301 to give a talk right (347). step). In addition, the media server 307 transmits a talk-taken message (TB_TAKEN: Talk Burst Taken, hereinafter referred to as 'TB_TAKEN') to the first terminal 301 in the current session. Except), it transmits to the terminals participating in the session, for example, the second terminal 309 and the third terminal 311 (steps 349 and 351).

The first terminal 301 having obtained the right to speak in the current session transmits an RTP message to the media server 307 (step 353), and the media server 307 transmits the RTP message to the third terminal 311. (Step 355). Here, the first terminal 301 knows a terminal that listens to its own speech, that is, a terminal capable of receiving an RTP message transmitted by the first terminal 301.

In the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims, but also by those equivalent to the scope of the claims.

As described above, the present invention provides a state in which a real-time transport protocol (RTP) message cannot be received in a current session in a push-to-talk over cellular (PoC) communication system. The UE transmits its own state information, that is, hold-on state information, to the UE which has sent a SUBSCRIBE message requesting information on UEs participating in the current session. Therefore, the terminal that transmits the SUBSCRIBE message in the current session acquires the right to speak, that is, when the RTP message is transmitted, the terminal that obtains the speaking right is a terminal capable of listening to its own speech, that is, it transmits itself. Since a terminal capable of receiving an RTP message can be known, a more efficient push-to-talk (PTT) service can be provided.

Claims (12)

In a push to talk (PTT) service providing system in a communication system, A terminal that transmits an information request message of terminals participating in a current session to a server providing a PTT service, and cannot receive a real-time transport protocol (RTP) message among terminals participating in the current session from the server. PTT service providing system comprising a specific terminal for receiving information of. The method of claim 1, The information on the state terminal that is unable to receive the RTP message received by the specific terminal PTT service providing system, characterized in that it comprises information of the hold_on state terminal. The method of claim 1, PTT service providing system, characterized in that the information of the state terminal that can not receive the RTP message received by the specific terminal is included in the notification (NOTIFY) message. In a push to talk (PTT) service providing system in a communication system, Receive the information request message of the terminals participating in the current session from the specific terminal, obtain the information of the state terminal that is unable to receive a real-time transport protocol (RTP) message among the terminals participating in the current session, And a server for transmitting the information of the state terminal that is unable to receive the RTP message in response to the request message. The method of claim 4, wherein The information of the state terminal that is unable to receive the RTP message obtained by the server PTT service providing system, characterized in that it includes information of the hold_on state terminal. The method of claim 4, wherein PTT service providing system, characterized in that the information of the state terminal that can not receive the RTP message obtained by the server is included in the notification (NOTIFY) message. In the method of providing a push to talk (PTT) service in a communication system, In the current session, the specific terminal, transmitting the information request message of the terminals participating in the current session to the server that provides a push-to-talk service to the terminal, A method for providing a PTT service, comprising receiving information from a state terminal that cannot receive a real-time transport protocol (RTP) message among terminals participating in a current session from the server. The method of claim 7, wherein The information on the state terminal that is unable to receive the RTP message includes the information on the hold_on state terminal. The method of claim 7, wherein The information on the state terminal that is unable to receive the RTP message is included in a NOTIFY message. In the method of providing push to talk (PTT) service in a communication system, The server, receiving the information request message of the terminals participating in the current session from the specific terminal, Acquiring information on a state terminal that is unable to receive a Real-time Transport Protocol (RTP) message among terminals participating in the current session; And transmitting information on a state terminal that is unable to receive the RTP message to the corresponding terminal in response to the request message. The method of claim 10, The information on the state terminal that is unable to receive the RTP message includes the information on the hold_on state terminal. The method of claim 11, The information on the state terminal that is unable to receive the RTP message is included in a NOTIFY message.

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