JP2010258802A - Communication system, communication terminal, communication method and communication program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the generation of a situation incapable of conducting communication by a nonmatching communication capacity between a communication terminal on a transmission side and that on the receiving side after transmission, and to conduct more efficient communication by an intended communication capacity. <P>SOLUTION: Each communication terminal A and B includes: a call control means 14 connecting a call specifying a voice call to the other communication terminal while establishing a capacity exchanging session for exchanging a capacity with the other communication terminal; and a capacity exchanging means 15 transmitting the communication capacity of its own communication terminal to the other communication terminal by using the capacity exchanging session and acquiring the communication capacity of the other communication terminal. Each communication terminal A and B further includes a capacity decision means 11 deciding the communication capacity usable for communications with the other communication terminal on the basis of the acquired communication capacity of the other communication terminal and the communication capacity of its own communication terminal. The call control means 14 specifies at least one of the usable communication capacities determined by the capacity decision means 11 and changes the communication capacity of the call connected for the other communication terminal. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a communication technique for communicating between terminals, and more particularly to a communication system, a communication terminal, a communication method, and a communication program for performing capability exchange.

  When performing multimedia communication such as videophone (multimedia communication), before starting transmission / reception of audio and video media, determine communication parameters such as audio encoding and video encoding used in the call. There is a need to.

  2. Description of the Related Art Conventionally, in a multimedia communication system using SIP (Session Initiation Protocol) and SDP (Session Description Protocol), it is necessary to perform a procedure called capability exchange between the terminal and the end-end terminal of the other terminal. .

  As a communication technique between terminals, for example, Patent Document 1 describes a communication connection method for connecting a communication path between a transmission side and a reception side using an out channel for line connection.

JP 07-058874 A

  Now, with the spread of information communication technology such as NGN (Next Generation Network), an environment capable of multimedia communication such as a videophone is being prepared. However, at present, multimedia communication terminals corresponding to multimedia communication are not widespread, and communication using only voice using a voice telephone is the center.

  In such a situation, when a call is made from a multimedia communication terminal such as a video phone to a voice phone, the communication capability of each device is different, so that the call is made with media that is not intended by the caller (for example, only voice). The problem of being started and the problem of not being able to connect to the phone occur.

  In recent years, a cooperation terminal that operates as a single communication terminal has appeared due to the cooperation of a plurality of devices. For example, a cooperation terminal that operates as a videophone terminal by performing video transmission / reception with a PC while making a voice call with a voice telephone by cooperation between a voice telephone and a PC (Personal Computer) has appeared. In such a cooperative terminal, the types and media of communication that can be realized differ depending on the communication capability held by the devices that are linked.

  Therefore, a means for grasping the communication capability held by the partner terminal of the other party is necessary. However, in the existing communication terminal using SIP and SDP, since the call connection function and the function for acquiring the communication capability of the counterpart terminal are combined, it is not possible to acquire only the capability of the counterpart terminal. SIP and SDP have a method called OPTIONS, but the load on the SIP server is large. Therefore, until the call is actually sent to the partner terminal and a response (OK or NG) is returned from the partner terminal, it is not known whether communication with the partner terminal is possible. Since the communication capability cannot be known, it is not known whether communication is possible or not unless the call is actually made.

  Moreover, in a cooperation terminal, it is assumed that the apparatus used as cooperation object changes frequently during a telephone call. When the device to be linked is changed, the communication capability that can be used during a call may be changed. In this case, in the existing SIP and SDP, it is necessary to transmit a capability exchange message. However, since this message passes through the SIP server, the load on the SIP server is increased.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to prevent the occurrence of a situation in which communication cannot be performed between the calling communication terminal and the receiving communication terminal after the transmission because the communication capabilities do not match. It is to prevent and perform more efficient communication with the intended communication capability.

  The present invention is a communication system having a plurality of communication terminals, wherein each communication terminal connects a call designating a voice call to another communication terminal and performs a capability exchange session for performing capability exchange with the other communication terminal. Call control means established between the communication terminal, the capability exchange means for transmitting the communication capability of the own communication terminal to another communication terminal using the capability exchange session, and acquiring the communication capability of the other communication terminal; Capability determining means for determining communication capability that can be used for communication with another communication terminal based on the communication capability of the other communication terminal and the communication capability of the own communication terminal, and the call control means, By specifying at least one of the usable communication capacities determined by the capability determining means, the communication capacities of the calls connected to other communication terminals are changed.

  Further, the present invention is a communication terminal for connecting a call designating a voice call to another communication terminal and establishing a capability exchange session for performing capability exchange with the other communication terminal; , Using the capability exchange session, the communication capability of the own communication terminal is transmitted to the other communication terminal, the capability exchange means for acquiring the communication capability of the other communication terminal, the acquired communication capability of the other communication terminal, Capability determining means for determining communication capability that can be used for communication with other communication terminals based on the communication capability of the communication terminal, and the call control means can be used as determined by the capability determining means The communication capability of the call connected to another communication terminal is changed by designating at least one of the different communication capabilities.

  The present invention also relates to a communication method for performing communication between communication terminals, including a call connection step for connecting a call specifying a voice call to another communication terminal, and a capability exchange session for performing capability exchange. A capability exchange session establishment step established between and a capability exchange step of transmitting the communication capability of the own communication terminal to another communication terminal using the capability exchange session, and acquiring the communication capability of the other communication terminal; Based on the acquired communication capability of the other communication terminal and the communication capability of the own communication terminal, a capability determination step for determining a communication capability that can be used for communication with the other communication terminal, and the determination in the capability determination step The change step of changing the communication capability of the call connected in the call connection step by designating at least one of the usable communication capabilities is performed.

  Moreover, this invention is a communication program which makes a computer perform the said communication method.

  According to the present invention, it is possible to prevent the occurrence of a situation in which communication cannot be performed between the calling communication terminal and the called communication terminal after transmission, and communication is not possible, and more efficient communication with the intended communication capacity. It can be performed.

1 is a configuration diagram of a communication system according to an embodiment of the present invention. A specific example of a communication terminal is shown. It is a sequence diagram which shows operation | movement of this embodiment. It is a sequence diagram for demonstrating the protocol of the operation | movement shown in FIG.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a diagram showing a system according to an embodiment of the present invention. In the present embodiment, communication is performed between End-End communication terminals. In the illustrated example, it is assumed that the communication terminal A and the communication terminal B communicate via a network (not shown). The communication terminals A and B are terminals that can make a call to a partner terminal and can receive a call from the partner terminal.

  The communication terminals A and B shown in the figure have a capability determination unit 11, a local terminal capability management unit 12, a counterpart terminal capability management unit 13, a call control unit 14, a capability exchange unit 15, and a media processing unit 16. .

  The capability determination unit 11 compares the communication capability of the partner communication terminal with the communication capability of the own communication terminal, and determines the communication capability that can be used with the partner communication terminal during a voice call.

  Note that the communication capability is the capability / function of each communication terminal. For example, when the communication terminal has a function of transmitting and receiving audio, the audio encoding method (G.711, G.729, etc.), audio encoding Encoding parameters used in the video format, and video encoding schemes (MPEG-2, MPEG-4, etc.) and video encoding schemes (image size: VGA, frame rate: 30 fps, bit rate: 3 Mbps, etc.) If you have media other than audio and video (material sharing, file transfer, etc.), parameters necessary for using the media, etc. The communication capability that can be used with the other communication terminal is determined.

  The own terminal capability management unit 12 holds and manages the communication capability (communication parameter) included in the own communication terminal, and manages the state of the own communication terminal. The partner terminal capability management unit 13 holds and manages the communication capability of the partner communication terminal acquired from the partner communication terminal.

  The call control unit 14 calls a partner communication terminal using a call connection protocol such as SIP, and establishes a session (establishes a call) for a voice call with the partner terminal. Further, the call control unit 14 receives a call transmitted from another communication terminal. Further, the call control unit 14 of the present embodiment establishes a capability exchange session for performing capability exchange with the counterpart terminal.

  After starting the voice call, the capability exchange unit 15 exchanges the communication capability with the counterpart communication terminal using the capability exchange session, and transmits the communication capability acquired from the counterpart communication terminal to the counterpart terminal capability management unit 13. sign up. The media processing unit 16 performs a voice call (sound transmission / reception), and transmits / receives a medium such as a video with a designated communication capability after the voice call is started.

  Each communication terminal described above can use, for example, a general-purpose computer system including at least a CPU, a memory, and an external storage device such as an HDD. In this computer system, each function of the communication terminal is realized by the CPU executing a predetermined program loaded on the memory.

  FIG. 2 shows a specific example of a communication terminal. The communication terminal in FIG. 2 (a) is a videophone, and all in-one (all in one) in which communication capability for voice call and video transmission / reception is supported in one terminal (housing). one) type communication terminal. In the case of such a communication terminal, the supported communication capability is fixed without being changed.

  FIG. 2B shows a cooperative communication terminal that realizes necessary communication capability (function) with a plurality of devices. In the illustrated example, a voice telephone for voice calls and a PC for video transmission / reception and document sharing function as one communication terminal. In the case of such a cooperation type communication terminal, the communication capability to be supported is not fixed because it varies depending on the device to be linked.

  Next, the operation of the system of this embodiment will be described.

  FIG. 3 is a sequence diagram showing the operation of the present embodiment. In this embodiment, when performing multimedia communication such as a videophone, first, a voice-only call is started between end-end communication terminals. At that time, a session for exchanging detailed capabilities (capability exchange session) is also simultaneously established between end-end communication terminals. If a capability exchange session cannot be established with the other terminal, only a voice call is performed. If a capability exchange session is established, the communication capability and status of each other's communication terminals are exchanged between the communication terminals after the voice call starts. To determine the available communication capability. Then, at any timing during a voice call, available communication capability can be added, and the added communication capability can be deleted.

  FIG. 3 shows an operation in the case of adding video and document sharing communication capability. Communication terminal A is a calling terminal and communication terminal B is a receiving terminal.

  The call control unit 14 of the calling terminal A uses SIP and SDP to specify a voice call as communication capability and to send / call to the receiving terminal B (S11). The call control unit 14 of the calling terminal A establishes a capability exchange session (TCP (Transmission Control Protocol) connection) (S12). The establishment of the capability exchange session is an exchange of information necessary for establishing a TCP connection necessary for performing capability exchange in S14 to S17 between the transmitting terminal A and the receiving terminal B.

  A voice call is started between the media processing unit 16 of the calling terminal A and the media processing unit 16 of the receiving terminal B by a call using SIP / SDP in S11 (S13).

  If a capability exchange session cannot be established in S12, it is determined that the partner terminal is a communication terminal (voice telephone) that cannot perform communications other than voice, and only voice calls are performed without performing the processes after S14. . Thereby, useless traffic can be reduced.

  If the capability exchange session can be established, the capability exchange session for exchanging the communication capabilities and states of the communication terminals is performed between the communication terminals using the capability exchange session after the voice call is started (S14).

  That is, the capability exchanging unit 15 of the calling terminal A acquires the communication capability and the state supported by the own terminal from the own terminal capability managing unit 12 and transmits the acquired communication capability to the receiving terminal B which is the counterpart terminal. The communication capability supported by the receiving terminal B and its state are received and stored in the counterpart terminal capability management unit 13. Similarly, the receiving terminal B transmits the communication capability and status of the own terminal set in the own terminal capability management unit 12 to the calling terminal A, and receives the communication capability and status of the calling terminal A from the calling terminal A. Store in the counterpart terminal capability management unit 13.

  The capability determining unit 11 of the calling terminal A then transmits the communication capability and status of the receiving terminal B stored in the counterpart terminal capability management unit 13 and the communication capability and status of the calling terminal A stored in the own terminal capability management unit 12. And the communication capability that can be used for communication with the receiving terminal B is determined (S15). Then, the capability determining unit 11 presents the determined usable communication capability to the user.

  Specifically, the capability determining unit 11 extracts and extracts the communication capability included in both the communication capability in the operable state of the calling terminal A and the communication capability in the operable state of the receiving terminal B. The determined communication capability is determined as the communication capability that can be used for communication with the receiving terminal B.

  For example, the communication capability of the receiving terminal B is “MPEG-4” as the video encoding method, and “image size: VGA, frame rate: 30 fps, bit rate: 3 Mbps” as the encoding parameters used in the video encoding method. "Document sharing" is set as a medium other than audio and video, while the communication capability of the calling terminal A is "MPEG-4 and MPEG-2" as the video encoding method. It is assumed that “image size: VGA, frame rate: 30 fps, bit rate: 3 Mbps” is set as an encoding parameter to be performed, and “material sharing” is set as a medium other than audio and video.

  In this case, the capability determination unit 11 of the transmitting terminal A uses “MPEG-4” as the video encoding method and “image size: VGA, frame rate: 30 fps, bit rate: as the encoding parameter used in the video encoding method. 3Mbps "is determined as" material sharing "as media other than audio and video.

  And the capability determination part 11 of the transmission terminal A displays the determined usable communication capability on output displays, such as a display, and receives the addition instruction | indication of media other than a voice from a user. In the illustrated example, it is assumed that an instruction to add video and material sharing is accepted.

  As a result, the capability determining unit 11 of the transmitting terminal A transmits a video and document sharing addition request to the receiving terminal B (S16). The capability determination unit 11 of the receiving terminal B transmits an additional response for video media and document sharing to the transmitting terminal A (S17).

  The communication capability intended by the calling terminal A (user) is determined between the calling terminal A and the receiving terminal B by the capability exchange session from S14 to S17.

  Then, the call control unit 14 of the calling terminal A transmits to the receiving terminal B an addition request (UPDATE request) in which video and material sharing is added in addition to voice as communication capability using SIP and SDP. The call control unit 14 of the receiving terminal B transmits an OK response to the addition request in S16 (S18). As a result, not only the voice call but also the transmission / reception of the added video and the data sharing are performed between the transmitting terminal A and the receiving terminal B (S19).

  Note that the capability exchange session from S14 to S17 is, for example, when the calling terminal A or the receiving terminal B is a device-linked communication terminal (see FIG. 2B), and the linked device is changed. This is done each time the communication capability changes.

  As described with reference to FIG. 3, in this embodiment, first, communication with a partner terminal is surely started by a voice call, and after a voice call is started, a detailed capability exchange is performed using a capability exchange session. A call (session) change request is transmitted using a call control protocol such as For this reason, in the present embodiment, it is possible to prevent the occurrence of a situation in which communication is not possible between the transmitting terminal and the receiving terminal after transmission and communication cannot be performed, and more efficient communication can be performed with the intended communication capacity.

  FIG. 4 is a sequence diagram for explaining the protocol of the operation shown in FIG.

  First, the call control unit 14 of the calling terminal A designates a voice call using a call connection protocol such as SIP, calls the called terminal B, and establishes a session for the voice call with the called terminal B. Open (establish call) (S11). Specifically, the call control unit 14 of the calling terminal A transmits an INVITE request specifying voice communication as the communication capability to the receiving terminal B, and the call control unit 14 of the receiving terminal B sends a response (200 OK) to the response. Transmit to calling terminal A.

  Then, the capability exchange unit 15 of the calling terminal A establishes a capability exchange session for performing detailed capability exchange with the receiving terminal B (S12). Specifically, as shown in FIG. 4, “SYN”, “SYN + ACK”, and “ACK” necessary for setting a TCP connection are transmitted and received. Information (IP address, port number, etc.) necessary for establishing a capability exchange session is transmitted and received by an INVITE request in S11 and “m = application” in 200 OK.

  With the call connection of S11, the media processing unit 16 of the calling terminal A and the media processing unit 16 of the receiving terminal B perform a voice call (S13).

  Then, the capability exchange unit 15 of the calling terminal A and the capability exchange unit 15 of the receiving terminal B use the capability exchange session (TCP connection) established in S12 to exchange the capability and status of each other's communication terminals. (S14).

  In FIG. 4, the processing of S15 to S17 described in FIG. 3 is omitted. However, in the capability exchange session, determination of usable communication capability (S15), addition request for determined communication capability (S16) Then, a response to the addition request (S17) is performed. Here, as in FIG. 3, it is assumed that an addition request for video and document sharing is made.

  Then, the call control unit 14 of the calling terminal A updates the call connected in S11 by specifying the communication capability for video and document sharing requested to be added in addition to the voice call (S18). Specifically, the call control unit of the calling terminal A transmits an UPDATE request designating voice communication, video, and document sharing as communication capabilities to the receiving terminal B, and the call control unit 14 of the receiving terminal B responds to it. (200 OK) is transmitted to the calling terminal A.

  Thereby, the media processing unit 16, the receiving terminal B, and the media processing unit 16 of the calling terminal A perform video transmission / reception and document sharing in addition to the voice call (S19).

  When the communication in S19 is completed, the call control unit 14 of the calling terminal A transmits BYE to disconnect the call, and the call control unit 14 of the receiving terminal B transmits a response (200 OK) to the call terminal A. (S20).

  Further, the call control unit 14 of the calling terminal A and the call control unit 14 of the receiving terminal B transmit and receive “FIN”, “ACK + FIN”, and “ACK” necessary for disconnecting the capability exchange session (TCP connection) ( S21).

  In the present embodiment described above, communication (voice communication) can be surely started with the counterpart terminal by starting communication from a voice call designating voice. In addition, by establishing a capability exchange session with the partner terminal, during the voice call, grasp the communication capability and status supported by the partner terminal, and add media other than voice without fail. Can do.

  That is, communication with a partner terminal is surely started by a voice call, and after a voice call is started, a detailed capability exchange is performed using a capability exchange session, and then a call (session) change request by a call control protocol such as SIP is requested. Therefore, in this embodiment, the occurrence of a situation in which communication is not possible between the calling terminal and the receiving terminal after communication is prevented and communication cannot be performed, and more efficient communication is performed with the intended communication capacity. Can do.

  Further, in the present embodiment, by directly opening a capability exchange session between End-End terminals, the load on the network (SIP server or the like) can be reduced.

  In the present embodiment, the communication terminal is a cooperation terminal in which a plurality of devices are linked, and the capability exchange session is used even when the device to be linked during a call is changed and the communication capability is changed. Thus, end-end terminals can be exchanged, and the communication capability used for communication with the partner terminal can be determined based on the changed communication capability.

  In addition, this invention is not limited to the said embodiment, Many deformation | transformation are possible within the range of the summary. For example, in the above embodiment, the capability exchange is performed using TCP as the capability exchange session. However, the present invention is not limited to this, and the capability exchange may be performed using, for example, UDP (User Datagram Protocol).

A, B Communication terminal 11 Capability determination unit 12 Own terminal capability management unit 13 Partner terminal capability management unit 14 Call control unit 15 Capability exchange unit 16 Media processing unit

Claims (7)

A communication system having a plurality of communication terminals,
Each communication terminal
A call control means for connecting a call designating a voice call to another communication terminal and establishing a capability exchange session for performing capability exchange with the other communication terminal;
Using the capability exchange session, the capability exchange means for transmitting the communication capability of the own communication terminal to another communication terminal and acquiring the communication capability of the other communication terminal;
Based on the acquired communication capability of the other communication terminal and the communication capability of the own communication terminal, having capability determination means for determining communication capability that can be used for communication with the other communication terminal,
The call control means specifies at least one of the usable communication capacities determined by the capability determination means and changes the communication capacities of the calls connected to other communication terminals. Communication system. The communication system according to claim 1,
The call control means performs connection of the call and change of communication capability of the call using SIP (Session Initiation Protocol),
The communication system characterized in that the capability exchange means performs capability exchange using TCP (Transmission Control Protocol) or UDP (User Datagram Protocol). A call control means for connecting a call designating a voice call to another communication terminal and establishing a capability exchange session for performing capability exchange with the other communication terminal;
Using the capability exchange session, the capability exchange means for transmitting the communication capability of the own communication terminal to another communication terminal and acquiring the communication capability of the other communication terminal;
Based on the acquired communication capability of the other communication terminal and the communication capability of the own communication terminal, having capability determination means for determining communication capability that can be used for communication with the other communication terminal,
The call control means specifies at least one of the usable communication capacities determined by the capability determination means and changes the communication capacities of the calls connected to other communication terminals. Communication terminal. The communication terminal according to claim 3, wherein
The call control means performs connection of the call and change of communication capability of the call using SIP (Session Initiation Protocol),
The communication terminal characterized in that the capability exchange means performs capability exchange using Transmission Control Protocol (TCP) or User Datagram Protocol (UDP). A communication method for performing communication between communication terminals,
A call connection step for connecting a call specifying a voice call to another communication terminal;
A capability exchange session establishment step for establishing a capability exchange session for performing capability exchange with another communication terminal;
Using the capability exchange session, the capability exchange step of transmitting the communication capability of the own communication terminal to another communication terminal and acquiring the communication capability of the other communication terminal;
A capability determination step for determining communication capability that can be used for communication with other communication terminals based on the acquired communication capability of the other communication terminal and the communication capability of the own communication terminal;
A communication method comprising: changing at least one of the usable communication capacities determined in the capability determination step and changing the communication capacities of the calls connected in the call connection step. . The communication method according to claim 5, comprising:
The call connection step and the change step perform connection of the call and change of communication capability of the call using SIP (Session Initiation Protocol),
The capability exchange step performs capability exchange using TCP (Transmission Control Protocol) or UDP (User Datagram Protocol).   A communication program for causing a computer to execute the communication method according to claim 5 or 6.

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