Bandwidth control in a mobile group communication system

0001The present invention relates to a broadcast communication system for communication through transmission and reception of data via a communication network among a plurality of user terminals, and particularly to a broadcast communication system for distributing received data to designated user terminals by accepting the data and designation of the data transmitting destination from any of the user terminals.

0002A communication group which is virtually formed on the network for making broadcast communication among a plurality of user terminals is called a "conference room". This conference room may have various profiles and forms a communication group with the communication partners designated by the user terminals.

0003In recent years, a transceiver technology utilizing a mobile communication network and a wireless LAN of cellular phones called PoC (Push-to-Talk over Cellular) and PoC/W (Push-to-Talk over Cellular/Wireless) has been put into the practical use. This transceiver function enables simultaneous voice communication to a plurality of partners on an IP communication network. A plurality of users, who can simultaneously communicate via voice are connected via a conference room on the network that is previously set or temporarily set. When a user, among those users connected in a same conference room, transmits a voice signal by acquiring the right to speak, the voice signals are distributed to the other users of the same conference room.

0004This transceiver function is primarily for communication by voice, but is capable of processing data for other than voice communication with improved cellular phones, for example. In addition, it is expected that communications will be further improved by distributing data for other than voice communication to the other users of the same conference room. However, the communication bandwidth for transmitting and receiving of the data is limited, particularly in the use of cellular phones. If voice and data communications other than voice are transmitted and received in combination, a delay and a fluctuation of the voice data are increased, resulting in a deterioration of a quality of the voice communication received. A method for avoiding such delay and fluctuation has been proposed to preset the communication bandwidth for voice communication and for the data other than the voice communication. However, in this method, if only one type of data is transmitted and received, since the communication network acquires respective data according to the preset fixed values, only the previously determined bandwidth is used. Thus, communication bandwidth reserved for data that is not transmitted is left unused, and thereby the available communication bandwidth is not used effectively. Thus, a problem exists that such conventional methods are inefficient in use of bandwidth.

0005A method has also been proposed in which information for varying a communication rate is collected from the user terminals taking part in the conference room whenever the right to speak is changed in the multiple-point conference system and the additional information such as picture information is distributed on the basis of the collected communication rate varying information. However, a problem still exists with such methods in that use of bandwidths is inefficient.

0006A plurality of users may conduct broadcast communications using a common conference room formed on the network, transmitting and receiving voice data and data other than the voice data. Deterioration in a quality of voice communication by a transmission and reception of the other data communications is prevented, and the limited communication bandwidth is used effectively. The quality of data, such as voice data and picture data, required to have realtime properties is influenced by the communication bandwidth both on the transmitting side and receiving side when such data is obtained and reproduced through communication. Moreover, the communication bandwidth varies according to a kind of network connecting the user terminals. Even when a plurality of user terminals of different available communication bandwidths are connected, means are provided to control the communication bandwidth so that the available communication bandwidth is effectively controlled.

0007In a broadcast communication system, data may be transmitted and received via a communication network among a plurality of identified user terminals. Advantages may be realized both for data that is primarily transmitted and received and for other data. The quality of the data which is mainly transmitted and received is influenced by the condition of communication in the broadcast communication system in which any of a plurality of identified user terminals transmits the data and the received data is distributed to the other user terminals.

0008A communication bandwidth may be controlled for transmitting or distributing data other than voice data. The bandwidth may be controlled in accordance with a receiving condition of the data, e.g., whether voice data, for example, is required to have a realtime property and whether the data other than the voice data is required to have a realtime property. A condition of the communication bandwidth may be observed for each user terminal that differs in accordance with the condition of communication within a group. A condition in a case of the communication system in which a right to speak is given to a user, among those in the user group in the group of a plurality of users, may be identified and a content of speech by the user who is given the right to speak may be distributed to the other users of the same group.

0009According to an aspect of the present invention, there is provided a communication bandwidth control method for controlling the bandwidth available for the transmission of non-voice data in a broadcast communication system comprising a plurality of user terminals, wherein one said user terminal is operable to transmit voice data to the other user terminals via a server, the method comprising, at the server: i) collecting values of communication bandwidths available to said user terminals and storing the collected values so as to correspond to information which identifies each of the plurality of user terminals; ii) verifying, upon receipt of non-voice data from one said user terminal, whether a right to transmit voice data has been acquired by any of said plurality of user terminals; and iii) setting, for each user terminal, a communication bandwidth for the transmission of the non-voice data to that terminal; wherein if it is verified that a right to transmit voice data has been acquired by one of said plurality of user terminals, then: a) in respect of the user terminal that has acquired the right to transmit voice data, the communication bandwidth set for the transmission of non-voice data from the server to that user terminal comprises an available transmission bandwidth; b) in respect of each user terminal that has not acquired the right to transmit voice data, the communication bandwidth set for the transmission of non-voice data from the server to that user terminal, is obtained by subtracting the bandwidth needed by the user terminal for receiving voice data from said available transmission bandwidth; wherein if it is verified that a right to transmit voice data has not been acquired by any of said plurality of user terminals, then: the communication bandwidth set for the transmission of non-voice data from the server to each of said plurality of user terminals comprises said available transmission bandwidth.

0010According to another aspect of the present invention, there is provided a server for use in a broadcast communication system comprising a plurality of user terminals, wherein one said user terminal is operable to transmit voice data to the other user terminals via said server, the server comprising: i) collecting means operable to collect values of communication bandwidths available to said user terminals and to store the collected values so as to correspond to information which identifies each of the plurality of user terminals; ii) verifying means operable, upon receipt of non-voice data from one said user terminal, to verify whether a right to transmit voice data has been acquired by any of said plurality of user terminals; and iii) setting means operable to set, for each user terminal, a communication bandwidth for the transmission of the non-voice data to that terminal; wherein, in response to the verifying means verifying that a right to transmit voice data has been acquired by one of said plurality of user terminals: a) in respect of the user terminal that has acquired the right to transmit voice data, the setting means is operable to set the communication bandwidth for the transmission of non-voice data from the server to that user terminal as comprising an available transmission bandwidth; b) in respect of each user terminal that has not acquired the right to transmit voice data, the setting means is operable to set the communication bandwidth for the transmission of non-voice data from the server to that user terminal by subtracting the bandwidth needed by the user terminal for receiving voice data from said available transmission bandwidth; wherein, in response to the verifying means verifying that a right to transmit voice data has not been acquired by any of said plurality of user terminals: the setting means is operable to set the communication bandwidth for the transmission of non-voice data from the server to each of said plurality of user terminals as comprising said available transmission bandwidth.

0011The server may calculate for each user terminal, a value obtained by subtracting the value of communication bandwidth required for transmission of first data from the value of communication bandwidth which the relevant user terminal can use as the communication bandwidth for transmission of second data, by referring, when the user terminal given the transmission right of the first data is not registered, to a database indicating the correspondence between the user terminals and the communication bandwidths which the relevant user terminal can use and setting the communication bandwidth which each user terminal can use as the communication bandwidth for transmission of the second data. The server also includes a second data distributing means for transmitting the second data to each user terminal in the communication bandwidth calculated by the second data communication bandwidth calculating means.

0012According to another aspect of the present invention, there is provided a communication bandwidth control method for controlling the bandwidth available for the transmission of non-voice data in a broadcast communication system comprising a plurality of user terminals, wherein one said user terminal is operable to transmit voice data to the other user terminals via a server, the method comprising, at the server: i) collecting values of communication bandwidths available to said user terminals and storing the collected values so as to correspond to information which identifies each of the plurality of user terminals; ii) determining, upon receipt of the non-voice data from one said user terminal, whether each user terminal is designated to receive voice-data and/or non-voice data; and iii) setting, for each user terminal, a communication bandwidth for the transmission of the non-voice data to that terminal, wherein: a) in respect of a user terminal which is designated to receive both voice and non-voice data, the communication bandwidth set for the transmission of non-voice data from the server to that user terminal is obtained by subtracting the bandwidth needed by said user terminal for receiving voice data, from an available transmission bandwidth, b) in respect of a user terminal which is designated to receive only non-voice data, the communication bandwidth set for the transmission of non-voice data from the server to that user terminal comprises said available transmission bandwidth.

0013According to another aspect of the present invention, there is provided a server for use in a broadcast communication system comprising a plurality of user terminals, wherein one said user terminal is operable to transmit voice data to the other user terminals via said server, the server comprising: i) collecting means operable to collect values of communication bandwidths available to said user terminals and to store the collected values so as to correspond to information which identifies each of the plurality of user terminals; ii) determining means operable, upon receipt of the non-voice data from one said user terminal, to determine whether each user terminal is designated to receive voice-data and/or non-voice data; and iii) setting means operable to set, for each user terminal, a communication bandwidth for the transmission of the non-voice data to that terminal, wherein: a) in respect of a user terminal which is designated to receive both voice and non-voice data, the setting means is operable to set the communication bandwidth for the transmission of non-voice data from the server to that user terminal by subtracting the bandwidth needed by said user terminal for receiving voice data, from an available transmission bandwidth; and b) in respect of a user terminal which is designated to receive only non-voice data, the setting means is operable to set the communication bandwidth for the transmission of non-voice data from the server to that user terminal as comprising said available transmission bandwidth.

0014The server may also include a second data storing means for storing second data transmitted from the user terminals corresponding to the identifying information of user terminal and the identifying information of user terminal of the second data transmitting destination. The server may also include a second data communication bandwidth calculating means for judging whether the relevant user terminal is stored in a first data storing means as the first data transmitting destination for the user terminal of the second data transmitting destination stored corresponding to the second data, calculating a value obtained by subtracting the communication bandwidth required for transmission of the first data from the communication bandwidth which the relevant user terminal can use as the communication bandwidth for transmission of the second data, when the relevant user terminal is stored as the first data transmitting destination. The server may also set the communication bandwidth which each user terminal can use as the communication bandwidth for transmission of the second data when the relevant user terminal is not stored as the first data transmitting destination. The server may also include a second data distributing means for transmitting the second data to the user terminal designated as the second data transmitting destination in the communication bandwidth calculated by the second data communication bandwidth calculating means.

0015Moreover, the quality of the first data may be removed from the influence of the user terminals transmitting the second data. The present invention may also be applied not only to a server, but also to user terminals.

0016According to another aspect of the present invention, there is provided a user terminal for transmitting non-voice data in a broadcast communication system comprising a plurality of user terminals, wherein one or more of said user terminals is operable to transmit voice data to another user terminal via a server, the terminal comprising: i) collecting means operable to collect values of communication bandwidths available to the plurality of user terminals of said communication system and to store the collected values so as to correspond to information which identifies each of the plurality of user terminals; ii) verifying means operable, following said user terminal requesting and acquiring a right to transmit non-voice data, to verify whether a right to transmit voice data has been acquired by any of said plurality of user terminals; iii) determining means operable to determine an available transmission bandwidth for transmissions from said given user terminal to said server; iv) non-voice data setting means for setting a communication bandwidth for the transmission of non-voice data from said user terminal to the server; wherein, in response to the verifying means verifying that a right to transmit voice data has been acquired by one of said plurality of user terminals: a) in response to the verifying means verifying that said user terminal comprises the user terminal that has acquired a right to transmit voice data, the non-voice data setting means is operable to set the communication bandwidth for transmitting said non-voice data from said user terminal to the server by subtracting the bandwidth used for transmitting said voice data from said user terminal to the server, from said available transmission bandwidth, wherein said available transmission bandwidth comprises the minimum bandwidth value selected from the values of the communication bandwidths available to: i) said user terminal, for transmissions therefrom to said server; and ii) said server, for transmissions therefrom to said other user terminals; b) in response to the verifying means verifying that said user terminal is not the user terminal that has acquired a right to transmit voice data, the non-voice data setting means is operable to set the communication bandwidth for transmitting said non-voice data from said user terminal to the server as comprising the available transmission bandwidth, wherein said available transmission bandwidth comprises the minimum bandwidth value selected from the values of: i) the value of the communication bandwidth available to said user terminal, for transmissions to said server; ii) the value of the communication bandwidth available to the user terminal that has acquired the right to transmit voice data, for transmissions to said server, and iii) the value(s) obtained by subtracting the bandwidth needed by the, or each, other user terminal that has not acquired the right to transmit voice data for receiving voice data from the value of the communication bandwidth available to that user terminal, wherein, in response to the verifying means verifying that a right to transmit voice data has not been acquired by any of said plurality of user terminals: the non-voice data setting means is operable to set the communication bandwidth for the transmission of non-voice data from said user terminal to the server as comprising the available transmission bandwidth, wherein said available transmission bandwidth comprises the minimum bandwidth value selected from: i) the value of the communication bandwidth available to said user terminal that has acquired the right to transmit voice data, for transmissions to said server; and ii) the values of the communication bandwidths available to the server for transmission to the other user terminals.

0017According to another aspect of the present invention, there is provided a communication bandwidth control method for controlling the bandwidth available for the transmission of non-voice data in a broadcast communication system comprising a plurality of user terminals, wherein one or more of said user terminals is operable to transmit voice data to another user terminal via a server, the method comprising, at a given user terminal: i) collecting values of communication bandwidths available to said user terminals and storing the collected values so as to correspond to information which identifies each of the plurality of user terminals; ii) following said given user terminal requesting and acquiring a right to transmit non-voice data, verifying whether a right to transmit voice data has been acquired by any of said plurality of user terminals; iii) determining an available transmission bandwidth for transmissions from said given user terminal to said server; iv) setting a communication bandwidth for the transmission of the non-voice data from said given user terminal to the server; wherein if it is verified that a right to transmit voice data has been acquired by one of said plurality of user terminals, then: a) if said given user terminal comprises the user terminal that has acquired a right to transmit voice data, then the communication bandwidth set for transmitting said non-voice data from said given user terminal to the server is determined by subtracting the bandwidth used for transmitting said voice data from said user terminal to the server, from said available transmission bandwidth, wherein said available transmission bandwidth comprises the minimum bandwidth value selected from the values of the communication bandwidths available to: i) said given user terminal, for transmissions therefrom to said server; and ii) said server, for transmissions therefrom to said other user terminals; b) if said given user terminal is not the user terminal that has acquired a right to transmit voice data, then the communication bandwidth for transmitting said non-voice data from said given user terminal to the server comprises the available transmission bandwidth, wherein said available transmission bandwidth comprises the minimum bandwidth value selected from the values of: i) the value of the communication bandwidth available to said user terminal, for transmissions to said server; ii) the value of the communication bandwidth available to the user terminal that has acquired the right to transmit voice data, for transmissions from said server, and iii) the value(s) obtained by subtracting the bandwidth needed by the, or each, other user terminal that has not acquired the right to transmit voice data for receiving voice data from the value of the communication bandwidth available to that user terminal, wherein if it is verified that a right to transmit voice data has not been acquired by any of said plurality of user terminals, then: the communication bandwidth set for the transmission of non-voice data from said given user terminal to the server comprises the available transmission bandwidth, wherein said available transmission bandwidth comprises the minimum bandwidth value selected from: i) the value of the communication bandwidth available to said user terminal that has acquired the right to transmit voice data, for transmissions to said server; and ii) the values of the communication bandwidths available to the server for transmission to the other user terminals.

0018According to another aspect of the present invention, there is provided a user terminal for transmitting non-voice data in a broadcast communication system comprising a plurality of user terminals, wherein one or more of said user terminals is operable to transmit voice data to another user terminal via a server, the user terminal comprising: i) collecting means operable to collect values of communication bandwidths available to the plurality of user terminals of said communication system and to store the collected values so as to correspond to information which identifies each of the plurality of user terminals; ii) downstream communication bandwidth determining means operable, following said given user terminal requesting and acquiring a right to transmit non-voice data for each user terminal of said communication system designated to receive said non-voice data, to determine a down-stream communication bandwidth for the transmission of said non-voice data from the server to the user terminal, wherein, in the case that said user terminal designated to receive said non-voice data is also designated to receive voice data, the downstream communication bandwidth determining means is operable to determine said down-stream communication bandwidth by subtracting the down-stream bandwidth needed for receiving said voice data from an available downstream bandwidth, and wherein, in the case that said user terminal designated to receive said non-voice data is not designated to receive voice data, the downstream communication bandwidth determining means is operable to determine said down-stream communication bandwidth as comprising the available down-stream bandwidth; iii) minimum down-stream communication bandwidth determining means operable to determine the value of the minimum down-stream communication bandwidth obtained by the downstream communication bandwidth determining means; iv) up-stream communication bandwidth determining means operable to determine an up-stream communication bandwidth for the transmission of the non-voice data from said given user terminal to the server wherein: a) in the case that said user terminal comprises the user terminal that has acquired a right to transmit voice data, the up-stream communication bandwidth determining means is operable to determine the up-stream communication bandwidth by subtracting the bandwidth used for transmitting said voice data from said user terminal to the server, from an available up-stream bandwidth; b) in the case that said user terminal is not the user terminal that has acquired a right to transmit voice data, the up-stream communication bandwidth determining means is operable to determine the up-stream communication bandwidth as comprising the available up-stream bandwidth; v) comparing means operable to compare the value of the up-stream communication bandwidth determined by the up-stream communication bandwidth determining means with the value of the minimum down-stream communication bandwidth determined by the minimum down-stream communication bandwidth determining means, wherein the up-stream communication bandwidth determining means is operable to set the minimum of these values to be the up-stream communication bandwidth for the transmission of non-voice data from said user terminal to the server.

0019According to another aspect of the present invention, there is provided a communication bandwidth control method for controlling the bandwidth available for the transmission of non-voice data in a broadcast communication system comprising a plurality of user terminals, wherein one or more of said user terminals is operable to transmit voice data to another user terminal via a server, the method comprising, at a given user terminal: i) collecting values of communication bandwidths available to said user terminals and storing the collected values so as to correspond to information which identifies each of the plurality of user terminals; ii) following said given user terminal requesting and acquiring a right to transmit non-voice data, determining, for each user terminal designated to receive said non-voice data, a down-stream communication bandwidth for the transmission of said non-voice data from the server to the user terminal, wherein if said user terminal designated to receive said non-voice data is also designated to receive voice data, said down-stream communication bandwidth is obtained by subtracting the down-stream bandwidth needed for receiving said voice data from an available downstream bandwidth, and wherein if said user terminal designated to receive said non-voice data is not designated to receive voice data, said down-stream communication bandwidth comprises the available down-stream bandwidth; iii) determining the value of the minimum down-stream communication bandwidth obtained in step ii); iv) determining an up-stream communication bandwidth for the transmission of the non-voice data from said given user terminal to the server wherein: a) if said given user terminal comprises the user terminal that has acquired a right to transmit voice data, then the up-stream communication bandwidth is determined by subtracting the bandwidth used for transmitting said voice data from said user terminal to the server, from an available up-stream bandwidth; b) if said given user terminal is not the user terminal that has acquired a right to transmit voice data, then the up-stream communication bandwidth comprises the available up-stream bandwidth; v) comparing the value of the up-stream communication bandwidth determined in step iv) with the value of the minimum down-stream communication bandwidth determined in step iii), wherein the minimum of these values is set to be the up-stream communication bandwidth for the transmission of non-voice data from said given user terminal to the server.

0020For a user terminal as described above, second data can be transmitted and received without giving any influence on the quality of first data in the user terminal side even when the server does not have the function for controlling the communication bandwidth.

0021According to an aspect of the present invention, second data other than first data can be transmitted and received without any deterioration in quality of the first data in the broadcast communication system in which any of a plurality of user terminals acquires the transmission right of the first data, transmits the first data, and distributes the first data transmitted from the relevant user terminal to the other user terminals of a plurality of user terminals via a communication network.

0022In addition, even if a communication bandwidth which the user terminals can use is different for each user terminal, the limited communication bandwidth can be used effectively since the communication bandwidth can be set, without relation to the communication bandwidths of the other user terminals, in accordance with the communication bandwidth, which the user terminals can use, for each user terminal. Moreover, since the second data can be distributed to the user terminals in the communication bandwidth which the user terminals can use, deterioration in the communication quality of the first data can be eliminated even if an illegal user terminal transmits intentionally a large amount of the second data. In addition, a user terminal having the transmission right of the second data is capable of effectively using the communication bandwidth when the second data is uploaded to the server.

0023Moreover, when the user terminal having acquired the transmission right of the second data is going to transmit the second data to the other user terminals, the communication bandwidth for transmission of the second data is set by calculating the communication bandwidths for the other user terminals which can be used for transmission of the second data, then comparing these bandwidths and then extracting the minimum communication bandwidth value and thereafter comparing the minimum value with the communication bandwidth which the user terminal having the transmission right of the second data can use for transmission of the second data. Accordingly, if the communication bandwidths which the user terminals can use are different from each other, the second data is never transmitted exceeding the communication bandwidth which the user terminal can use and the second data can be transmitted and received without deterioration in transmission quality of the first data.

0024Particularly, in the case where the first data is voice and picture data, communication may be realized while the information other than the voice and picture data is transmitted and received. In this case, deterioration in the quality of voice and picture data due to the transmission and reception of the information other than the voice and picture data can be prevented.

0025A system may broadcast communication among a plurality of terminals by, for example, a voice signal generated from one terminal is broadcast to the other terminals, on the IP (Internet Protocol) network. Accordingly, at the time of broadcast communication, voice data communication and data other than the voice data, such as picture and text, can be transmitted and received simultaneously. Further, the communication bandwidth for transmission and reception of the data other than the voice data can be controlled in accordance with transmission and reception of voice data. Therefore, data other than the voice data can be transmitted and received effectively without deterioration in the quality of voice communication voices during broadcast communication.

0026Reference will now be made, by way of example, to the accompanying drawings, in which: <ul id="ul0001" list-style="none" compact="compact"><li><figref idref="f0001">Fig. 1</figref> is a block diagram illustrating a broadcast communication system;</li><li><figref idref="f0002">Fig. 2</figref> is a flow chart illustrating an operation of the broadcast communication system;</li><li><figref idref="f0003">Fig. 3</figref> is a block diagram illustrating an example of a display format;</li><li><figref idref="f0004">Fig. 4</figref> is a block diagram illustrating an example of a display format;</li><li><figref idref="f0005">Fig. 5</figref> is a block diagram illustrating an example of a user management unit;</li><li><figref idref="f0005">Fig. 6</figref> is a block diagram illustrating an example of a PTT management unit;</li><li><figref idref="f0006">Fig. 7</figref> is a block diagram illustrating an example first embodiment of a of a broadcast communication system acceding to the present invention;</li><li><figref idref="f0007">Fig. 8</figref> is a flowchart illustrating an example, of communication bandwidth control according to the first embodiment;</li><li><figref idref="f0008">Fig. 9</figref> is a block diagram illustrating an example of a display format;</li><li><figref idref="f0009">Fig. 10</figref> is a block diagram illustrating another example of a display format;</li><li><figref idref="f0010">Fig. 11</figref> is a block diagram illustrating an example of a broadcast communication system according to a second embodiment of the present invention;</li><li><figref idref="f0011">Fig. 12</figref> is a flow chart illustrating processes for communication bandwidth control according to a second embodiment of the present invention;</li><li><figref idref="f0012">Fig. 13</figref> is a block diagram illustrating an example of a down-stream bandwidth storage unit;</li><li><figref idref="f0013">Fig. 14</figref> is a block diagram illustrating an example of a distribution data storage unit;</li><li><figref idref="f0014">Fig. 15</figref> is a block diagram illustrating an example of display format;</li><li><figref idref="f0015">Fig. 16</figref> is a flow chart illustrating voice control processes of the broadcast communication system;</li><li><figref idref="f0016">Fig. 17</figref> is a block diagram illustrating an example of display format;</li><li><figref idref="f0016">Fig. 18</figref> is a block diagram illustrating an example of content of a voice recording unit;</li><li><figref idref="f0017">Fig. 19</figref> is a flow chart illustrating processes for communication bandwidth control in a third embodiment according to the present invention;</li><li><figref idref="f0018">Fig. 20</figref> is a flow chart illustrating for communication bandwidth control in a fourth embodiment; and</li><li><figref idref="f0019">Fig. 21</figref> is a flow chart illustrating another example of the PTT management unit.</li></ul>

0027<figref idref="f0001">Fig. 1</figref> illustrates an example of a broadcast communication system according to an aspect of the present invention.

0028The broadcast communication system includes a plurality of terminals 1T1, 1T2, ... hereinafter, a terminal is generally expressed as "terminal 1T") which are connected via a server 1S for management and control of the broadcast communication and various networks 1 N 1, 1N2, 1N3, 1N4, ...(hereinafter, a network is generally expressed as "network 1 N"). The terminal 1T and server 1S are connected for communication via various networks 1Ns. The network 1N1 and the network 1N2 may be a wireless communication network such as cellular phones. Moreover, the network 1N3 may be a wired network such as a LAN (Local Area Network) .

0029The server 1S includes an IP communication unit 100, a PTT processing unit 101, a user management unit 310, and a PTT management unit 110.

0030The IP communication unit 100 is an interface for transmitting the information to the network 1N from the server 1S and acquiring the information from the network 1N.

0031The PTT processing unit 101 is a processing unit for executing the processes designated by a command through interpretation thereof when the command received from the IP communication unit 100 is an instruction relating to the broadcast communication system.

0032The user management unit 310 is a database storing the information for users.

0033The PTT management unit 110 is a database storing the application condition of the broadcast communication system.

0034Each terminal 1T includes an IP communication unit 200, a voice data control unit 203, a PTT processing unit 201, a voice recording unit 206, and a user interface unit 204.

0035The IP communication unit 200 is an interface for transmitting the information to the network 1 N from the terminal 1T and acquiring the information from the network 1N.

0036The voice data control unit 203 is a processing unit for conducting the processes such as encoding/decoding of the voice data to be transmitted and received.

0037The PTT processing unit 201 generates a command for the broadcast communication system transmitted to the server 1S by accepting user inputs from the terminal 1T via the user interface unit 204 and executes the command through interpretation for the broadcast communication system received from the server 1S.

0038The voice recording unit 206 is provided for management of the terminal 1T having acquired the right to speak in the conference room to which the terminal 1T participates.

0039The user interface unit 204 displays various menus for utilizing the broadcast communication system on the display area of the terminal 1T, acquires contents of input from the menus displayed on the display unit and from the contents of input keys selected, and notifies such contents to the PTT processing unit 201.

0040An example flow of the broadcast communication system is described with reference to <figref idref="f0002 f0003 f0004 f0005">Fig. 2 to Fig. 6</figref>.

0041Users of the terminal 1T acquire a user ID for utilizing the broadcast communication system and are registered to the user management unit 310 together with the user information. An example of the user management unit 310 is illustrated in <figref idref="f0005">Fig. 5</figref>. The user management unit 310 includes various items such as user ID 51, display name 52, name 53, address 54, etc. The user ID 51 is the user ID required for a user to utilize the broadcast communication system and is set uniquely in the broadcast system. The display name 52 is the name to be displayed for displaying a list of users. The items to be registered to the user management unit 310 may be determined with a system manager or an administrator. The name 53 and address 54, etc. indicated in <figref idref="f0005">Fig. 5</figref> are examples of the items requested for registration as the user information from the system manager or administrator. The system manager or administrator is capable of urging the user to input the other necessary items such as company name or section. These items may be associated with an existing individual information database.

0042In the following example, broadcast communication among a terminal 1T1 (user: ichiro horio), a terminal 1T2 (user: jiro ohno), and a terminal 1T3 (user: saburo okuyama) is assumed.

0043When the user acts to display a menu of the broadcast communication service at the terminal 1T1, the user interface unit 204 displays a user list for designating partners for making broadcast communication, as illustrated in <figref idref="f0003">Fig. 3</figref>. In this user list, the users who are capable of utilizing the broadcast communication service are displayed with the display names 52 registered to the user management unit 310. This user list is also capable of displaying all users subscribed to the broadcast communication service. It is also possible that only those users requested by a user for each terminal among the users participating to the broadcast communication service are selectively registered and only the registered users are display in the list.

0044Moreover, it is possible to form groups of users, a name being given to each group, and the selected group name is displayed. The "Okuyama group" and "VoIP group" displayed in the member selection display format of <figref idref="f0003">Fig. 3</figref> are examples of a display of the group name. When the group name is selected, all users corresponding to the group are selected or the users registered in the group are displayed one time in the list, and thereafter members are selected from the list.

0045Moreover, it is also possible to display a conference room name from among conference rooms to which the users of the terminal 1T are registered as members, or to display a conference room name from among the conference rooms that are temporarily open. When the conference room name is selected and the PTT start button BT31 is selected, the selected conference room name and the user ID of the terminal 1T are provided to the PTT processing unit 201. The PTT processing unit 201 generates a PTT participation statement command and provides this command to the server 1S via the IP communication unit 201. The PTT participation statement command includes an identifier indicating the PTT participation statement command and a conference ID for identifying the conference room for participation.

0046A user of the terminal 1T identifies partners requested for broadcast communication from the user list displayed on the display screen. Moreover, when the user selects the PTT start button BT31, the selected users and the information indicating that the PTT start button BT31 is selected are provided to the PTT processing unit 201 via the user interface unit 204. The PTT processing unit 201 generates a PTT start command and transmits this command to the server 1S via the IP communication unit 200. The PTT start command includes an identifier indicating the PTT start request and a user ID of the designated partner. Since "ohno" and "okuyama" are selected in the example of <figref idref="f0003">Fig. 3</figref>, the user IDs of "ohno" and "okuyama" are obtained with reference to the user management unit 310 to generate the PTT start command and this PTT start command is transmitted to the server 1 S.

0047The server 1 S generates, upon reception of the PTT start command transmitted from the terminal 1T1 (Yes in operation 2010 of <figref idref="f0002">Fig. 2</figref>), a conference room for broadcast communication. When the conference room is generated, a conference room ID is generated to identify the relevant conference room. In this example, "PocSes001" is generated as the conference room ID. The information for management and control of the conference room corresponding to the generated conference room ID is registered to the PTT management unit 110 (2020 of <figref idref="f0002">Fig. 2</figref>).

0048An example of a PTT management unit 110 is illustrated in <figref idref="f0005">Fig. 6</figref>. The PTT management unit 101 conference room ID information 61, member information 62, participant information 63, and voice information 64. In the conference room ID information 61, a generated conference room ID is set. In the member information 62, a user ID of the user who is recognized as the participant to the relevant conference room is registered. When the PTT start command is received, the user ID designated by the PTT start command is set as the user who is recognized as the participant for the relevant conference room. In the participant information 63, the user ID of the user who is actually participating to the conference room is set. In voice information 64, the user ID of the terminal 1T which is recognized for voice is set on the basis of the voice request command transmitted from the user who is participating to the conference room. Moreover, when the conference room is permanently open, the conference room ID and the user ID recognized to participate in this conference room are always registered to the member column until the permanent conference room is deleted. For, example, the conference room information of the conference room ID:PoCSes901 illustrated in <figref idref="f0005">Fig. 6</figref> is the permanently open conference room and three users of the user ID:abc@ffPoC.com, user ID:bcd@ddPoC.com, and the user ID:efg@ppPoC.com are registered as the members. In the illustrated example, a user is not currently participating in the conference room. However, since the conference room is a permanently open conference room, the conference room information is still registered with the PTT management unit 110.

0049The PTT processing unit 101 guides a user (user ID:horio@fujipoc.com) of the terminal 1T1 to the generated conference room (conference room ID:SesPoc001) and sets the user ID:horio@fujipoc.com of the terminal 1T1 to the item of the participant 63 of the conference room ID:"PoCSes001" of the PTT management unit 110. Moreover, the PTT processing unit 101 notifies terminal 1 of information such as a conference room ID of a conference room being opened and an address and a port number of a server which are required for transmission of data to the conference room (2030 of <figref idref="f0002">Fig. 2</figref>).

0050The PTT processing unit 101 verifies whether a communication partner designated with the PTT start command is in the condition to enable the IP communication.

0051When the terminal 1T of the communication partner is in a condition to enable the IP communication (Yes in operation 2040 of <figref idref="f0002">Fig. 2</figref>), the terminal 1T transmits a PTT calling command (2050 of <figref idref="f0002">Fig. 2</figref>). The PTT calling command includes an identifier indicating the PTT calling command, a conference room ID, address and port number of the server for transmitting the voice data, and a member name. For example, when the terminal 1T3 (user:okuyama) is in the condition to enable the IP communication, "PoCSes001" is set to the item of the conference room ID of the PTT calling command, the address and port number of the server are set to the item of the address and port number of the server, and the user IDs:horio@fujipoc.com, ohno@fujipoc.com and okuyama@fujipoc.com of users who are recognized to participate to this conference room are set to the item of member, and these are transmitted to the terminal 1T3 from the server 1S (2050 of <figref idref="f0002">Fig. 2</figref>).

0052When the terminal 1T of the communication partner is not in a condition to enable the IP communication (No in operation 2040 of <figref idref="f0002">Fig. 2</figref>), a message requesting execution of the connection process, to set the condition to enable the IP communication with a protocol which is different from the IP, is transmitted to the terminal 1T of the communication partner. For example, when the terminal 1T2 (user:Ohno) is not in a condition to enable IP communication, the server 1S transmits the message instructing an execution of the connecting process to set the condition to enable the IP communication by making use of a SMS (short message system) to the terminal 1T2. The terminal 1T2, having received the message instructing execution of the connecting process to set the condition to enable the IP communication, executes the connecting process for the IP communication and sends a message indicating completion of the connecting process to the server 1S.

0053When the terminal 1T verifies the condition to enable the IP communication (Yes in operation 2310 of <figref idref="f0002">Fig. 2</figref>), this terminal transmits the PTT calling command to the terminal 1T2 (2050 of <figref idref="f0002">Fig. 2</figref>). If the condition to enable the IP communication cannot be verified (No in 2310 of <figref idref="f0002">Fig. 2</figref>), an error process is performed. As an example of the error process, a message "connection failure" is sent to the other terminals of the participants, or the connecting message is repeatedly transmitted so a condition to enable IP communications can be attained.

0054When the command received from the terminal 1T is not the PTT start command (No in operation 2010 of <figref idref="f0002">Fig. 2</figref>), the server 1S determines whether the command received from the terminal 1T is the PTT participation request command. When the command is the PTT participation request command (Yes in 2500 of <figref idref="f0002">Fig. 2</figref>), the member 62 being stored corresponding to the conference room ID designated in the PTT participation request command is compared with contents of the participant 63 to extract the users who are members but are not participating to the conference room (2510 of <figref idref="f0002">Fig. 2</figref>). The PTT calling command is transmitted to the extracted users (20509 of <figref idref="f0002">Fig. 2</figref>).

0055When the command received from the terminal is not the PTT participation request command (No in operation 2500 of <figref idref="f0002">Fig. 2</figref>), whether the command received from the terminal is the PTT participation statement command is determined. When the command received from the terminal is the PTT participation statement command (Yes in operation 2600 of <figref idref="f0002">Fig. 2</figref>), whether the user having transmitted the participation statement command is registered to the member 62, which is stored corresponding to the conference room ID designated with the participation statement command, is verified with reference to the PTT management unit 110. When the user is registered as the member, this user is guided to participate in the conference room.

0056The terminals 1T2, 1T3, having received the PTT calling command, participate in the conference room by storing the conference room ID, address and port number of the server for transmitting the voice data, and member name set in the PTT calling command in the storage unit (2060 of <figref idref="f0002">Fig. 2</figref>).

0057The PTT processing unit 101 registers the user IDs of the terminals 1T2, 1T3 as participants in participant 63 of the conference room ID:PoCSes001 of the PTT management unit 110.

0058Accordingly, the broadcast communications by three parties of, for example, user names "horio", "ohno", and "okuyama" occurs in the conference room of the conference room ID:PoCSes001. <figref idref="f0004">Fig. 4</figref> illustrates an example of a display format on the terminal 1T when the broadcast communication becomes possible. The user:horio of the terminal 1T, who has issued the PTT start command, is displayed in the first line of a user list. The users:ohno and okuyama, designated as the communication partners are also displayed to the next and subsequent lines of the list as the users who are simultaneously communicating in this conference room.

0059Upon reception of a PTT completion request (Yes in 2070 of <figref idref="f0002">Fig. 2</figref>), the PTT processing unit 101 completes the conference. When the conference room designated in the PTT completion request is permanently opened, all user IDs registered to participant 63 of the PTT management unit 110 are deleted. If the conference room designated in the PTT completion request is not the permanently open conference room, information of the conference room stored and designated in the PTT management unit 110 is deleted (2700 of <figref idref="f0002">Fig. 2</figref>).

0060If the PTT completion request is not yet received (No in 2070 of <figref idref="f0002">Fig. 2</figref>), whether a PTT leaving command is received is verified. When the PTT leaving command is received (Yes in 2073 of <figref idref="f0002">Fig. 2</figref>), the leaving user ID is deleted from the participant information 63, of the conference room ID stored in the PTT management unit, on the basis of the conference room ID designated in the PTT leaving command and the leaving user ID (2076 of <figref idref="f0002">Fig. 2</figref>).

0061If the PTT leaving request is not yet received (No in 2073 of <figref idref="f0002">Fig. 2</figref>), whether a voice acquiring request has been received is judged. When the terminal 1 T wants to acquire the voice data, a user of the terminal 1 T is requested to select the voice acquiring button BT41 on the display format (<figref idref="f0004">Fig. 4</figref>) displayed on the terminal 1T. The user interface unit 204 notifies the PTT processing unit 201 that the voice acquiring button BT41 is selected. The PTT processing unit 201 generates a voice acquiring request command and then transmits this command to the server 1 S.

0062When the server 1S has received the voice acquiring request (Yes in 2080 of <figref idref="f0002">Fig. 2</figref>), the PTT processing unit 101 determines whether it is possible to provide the voice data. When it is possible to provide the voice data (Yes in 2090 of <figref idref="f0002">Fig. 2</figref>), the user ID of the terminal 1T having requested the voice data is registered, or the user ID is updated in the voice information 63 of the relevant conference room ID of the PTT management unit 110, and sent to the terminal 1T having requested the voice data that the voice data has been obtained. Moreover, the user ID of the terminal 1T having acquired the voice data is provided to the other terminals 1T participating in the same conference room (2100 of <figref idref="f0002">Fig. 2</figref>). In this case, the terminal 1T stores upon reception of the notification that the voice data has been obtained, or upon notification of the user ID having acquired the voice data, the user ID of the terminal 1T having acquired the voice data to the voice recording unit 206. If it is not possible to provide voice data in the process of the server 1S (No in 2090 of <figref idref="f0002">Fig. 2</figref>), the voice requesting terminal 1T is notified that the voice cannot be obtained, or a process is performed to register the voice requesting terminal 1T in a queue for acquiring the voice (2130 of <figref idref="f0002">Fig. 2</figref>).

0063When the voice data is received from the terminal 1T having acquired the voice (Yes in 2110 of <figref idref="f0002">Fig. 2</figref>), the user ID of a user who does not have the voice data is extracted from among the user IDs of the participants stored in the relevant conference room ID of the PTT management unit 110. Thee voice data received is transmitted to the terminal of the relevant user ID (2120 of <figref idref="f0002">Fig. 2</figref>).

0064When the command received from the terminal 1T is not the voice acquiring request (No. in 2080 of <figref idref="f0002">Fig. 2</figref>), whether the command received from the terminal 1T is a voice canceling command is determined.

0065When the voice canceling command is received (Yes in 2800 of <figref idref="f0002">Fig. 2</figref>), the PTT processing unit 101 deletes the user ID designated from the item of voice 63 of the conference room ID stored in the PTT management unit 110 on the basis of the conference room ID and user ID for canceling the voice designated in the voice canceling command. Moreover, a message informing whether the voice data request is cancelled is sent to the terminal 1T participating to the relevant conference room (2800 of <figref idref="f0002">Fig. 2</figref>). Upon reception of the message indicating the voice request has been cancelled from the server 1S, the content recorded in the voice recording unit 206 is deleted. Moreover, the server 1S determines whether the terminal 1T waiting for the voice data is registered in the waiting queue. When the terminal 1T is registered to the queue (Yes in 2820 of <figref idref="f0002">Fig. 2</figref>), whether the voice should be given is determined by returning to the step 2090.

0066Broadcast communication can occur among a plurality of terminals according to the procedures described above.

0067Next, a method of communication bandwidth control for transmission of reception of data other than voice data while the broadcast communication is conducted is described.

0068In the following description of the example embodiments, the elements having the functions similar to those described above are designated with the similar reference numerals and the identical descriptions are omitted.

0069According to an example first embodiment, an example of controlling the communication bandwidth for transmission of data other than the voice data from the terminal side is described.

0070<figref idref="f0006">Fig. 7</figref> illustrates an example first embodiment.

0071A server 2S for controlling the broadcast communication among a plurality of terminals 2T1, 2T2, 2T3, 2T4, ...(hereinafter, generally referred to as a "terminal 2T) connected for enabling the communication via various networks 2N1, 2N2, ...(hereinafter, generally referred to as "network 2N") is illustrated. For example, a network 2N1 as a cellular phone network provided by a cellular phone company A, a communication system CDMA 1x (Code Division Multiple Access 1 x) system, network 2N2 as cellular phone communication network provided by a cellular phone company B, and a communication system as the PHS (Personal Handyphone System) system are illustrated. Moreover, the example network 2N3 is a wired network such as a LAN (Local Area Network). The server 2S for management of the broadcast communication is connected to each network 2N1, 2N2, ...via the network such as the LAN.

0072The server 2S also includes a data transmission right control/recording unit 102 in addition to items included in server 1S described above. The data transmission right control/storage unit 102 controls providing a data transmission right to the terminal 2T or canceling the transmission right. Moreover, the terminal 2T also includes, in addition to the items included in the terminal 1T described above a data transmission right recording unit 207, a distributing data transmission rate control unit 202, and a transmission enabling bandwidth determining means 205. The data transmission right recording unit 207 stores the information indicating acquisition of the transmission right when the terminal 2T requests the transmission right to the server 2S and then receives the message indicating the data transmission right is given from the server 2S. The distributing data transmission rate control unit 202 controls the communication bandwidth for transmission of data in accordance with the communication condition in the conference room. The transmission enabling bandwidth determining unit 205 collects the information of the communication bandwidths of the terminals of the other users participating in the conference room and calculates the communication bandwidth for transmission.

0073For example, broadcast communication by the terminal 2T1 (user:horio) with the terminal 2T2 (user:ohno) and the terminal 2T3 (user:okuyama) is assumed. With execution of operations 2010 to 2050 illustrated in <figref idref="f0002">FIG. 2</figref>, broadcast communications by three parties can be started.

0074The terminal 2T1 acquires, when it participates in the conference room, information regarding the communication bandwidths of the other terminals from the other terminals 2T2, 2T3 which are also participating in the conference room (8010 of <figref idref="f0007">Fig. 8</figref>). Example information regarding the communication bandwidths includes the up-stream and down-stream bandwidths and minimum guaranteed up-stream and down-stream bandwidths. In this example, "up-stream" refers to the transmission of data toward the server 2S from the terminal 2T, while "down-stream" refers to the transmission of data toward the terminal 2T from the server 2S. This definition also applies in the example second embodiment. The terminal 2T2 is connected to the network 2N1 and the communication system is the CDMA 1x system. Therefore, information regarding communication bandwidth, e.g., the up-stream communication bandwidth of 64 kbps, down-stream communication bandwidth of 144 kbps, minimum guarantee bandwidth of up-stream of 9.6 kpbs, and minimum guarantee bandwidth of down-stream of 9.6 kpbs is acquired. Moreover, since the terminal 2T3 is connected to the network 2N2 and the communication system is a PHS system the information regarding communication bandwidth, e.g., the up-stream communication bandwidth of 64 kpbs, down-stream communication bandwidth of 64 kpbs, minimum guaranteed bandwidth of up-stream of 64 kpbs, and the minimum guarantee bandwidth of down-stream of 64 kbps are acquired.

0075Transmission of a picture taken by the terminal 2T1 to the other participants of the conference room while terminal 2T1 is participating in the conference room (conference room ID:PoCSes001) will be described as an example.

0076<figref idref="f0008">Fig. 9</figref> illustrates a display example on a display screen for photography. In this example, a menu for photography is included into a menu of the broadcast communication system and pictures obtained are distributed to the other terminals. It is also possible, in addition to this example, to upload pictures obtained by other means.

0077When a camera is directed at an object and a photography button BT91 is selected in the terminal 2T1, a picture of the object is generated and a request of a data transmission right for transmitting the generated picture data to the other terminals 2T2, 2T3 is transmitted to the server 2S (8020 of <figref idref="f0007">Fig. 8</figref>). The server 2S records the user ID of the terminal 2T which is recognized to have the data transmission right and also notifies acknowledgment of the data transmission right to the request generating terminal 2T1. The terminal 2T1 verifies, upon reception of acknowledgment of data transmission right (Yes in 8030 of <figref idref="f0007">Fig. 8</figref>), whether the terminal using voice in the conference room to which the relevant terminal 2T1 is also participating exists.

0078When the terminal using voice exists (Yes in 8040 of <figref idref="f0007">Fig. 8</figref>), it is verified whether the terminal 2T using voice is the terminal 2T1 having a data transmission right.

0079When the terminal 2T1 having the data transmission right has acquired the voice data (Yes in 8050 of <figref idref="f0007">Fig. 8</figref>), the bandwidth of the data transmission is determined by the following example procedures.

0080When the terminal 2T1 has acquired both a data transmission right and voice, only the terminal 2T1 transmits both voice data and other data in the conference room. The other terminals 2T2, 2T3 participating in the conference room only receive the voice data communication and the data other than the voice data. Therefore, the up-stream communication bandwidth of the terminal 2T1 is compared with a minimum communication bandwidth among the down-stream communication bandwidths of the other terminals 2T2, 2T3 participating in the conference room. When the up-stream communication bandwidth of the terminal 2T1 is greater than the minimum communication bandwidth among the down-stream communication bandwidths of the other terminals 2T2, 2T3, the value of the minimum communication bandwidth among the down-stream communication bandwidths is calculated as the transmission enabling communication bandwidth of the terminal 2T1. A communication bandwidth for data transmission is determined by subtracting the bandwidth used for voice communication from this calculated transmission enabling bandwidth.

0081When the minimum communication bandwidth among the down-stream communication bandwidths of the other terminals 2T2, 2T3 is greater than the up-stream communication bandwidth of the terminal 2T1, the value of the up-stream communication bandwidth of the terminal 2T1 is calculated as the transmission enabling communication bandwidth of the terminal 2T1. The transmission bandwidth for data transmission is obtained by subtracting the bandwidth used for transmission of voice data from this calculated transmission enabling bandwidth.

0082An example follows. Since the terminals 2T1, 2T2 are connected to the network 2N1 and the communication system is the CDMA 1x system, the up-stream communication bandwidth is 64 kbps, the down-stream communication bandwidth is 144 kbps, the minimum guaranteed bandwidth for up-stream communications is 9.6 kbps, and the minimum guaranteed bandwidth for down-stream is 9.6 kbps. Since the terminal 2T3 is connected to the network 2N2 and the communication system is a PHS system, as the information of the communication bandwidth, the up-stream communication bandwidth is 64 kbps, down-stream communication bandwidth is 64 kbps, the minimum guaranteed bandwidth of up-stream is 64 kbps, and the minimum guaranteed bandwidth of down-stream is 64 kbps. The minimum guaranteed bandwidths down-stream of the terminals 2T2 and 2T3 respectively are 9.6 kbps and 64 kbps and the minimum value is 9.6 kbps.

0083Since the minimum guaranteed bandwidth of 9.6 kpbs up-stream of the terminal 2T1 is equal to the minimum guaranteed bandwidth of 9.6 kbps down-stream of the terminals 2T2 and 2T3, the transmission enabling bandwidth of the terminal 2T1 is calculated as 9.6 kbps. The bandwidth for transmission of voice data is determined with the voice data compression system (CODEC) and transmission interval. In this example, a communication bandwidth of 5.9 kbps is required for transmission of the voice data. Since the terminal 2T1 uses voice, it is required to acquire a bandwidth for transmission of the voice data. Therefore, the communication bandwidth for transmission of data is calculated as 3.7 kbps, which is equal to the remainder of the bandwidth after subtraction of the bandwidth for transmission of voice data of 5.9 kbps from the transmission enabling bandwidth of 9.6 kbps (8060 of <figref idref="f0007">Fig. 8</figref>).

0084When the terminal 2T having the data transmission right does not have a voice transmission right (No in 8050 of <figref idref="f0007">Fig. 8</figref>), the bandwidth for data transmission is determined in accordance with the following example.

0085In this case, the terminal 2T has only a data transmission right and transmits the data with an up-stream communication bandwidth and receives the voice data from the other terminal 2T with a down-stream communication bandwidth. The terminal 2T using only voice transmits the voice data with the up-stream communication bandwidth and receives the data with the down-stream communication bandwidth. The terminal 2T having neither a voice nor data transmission right receives both the voice data and the data other than the voice data with a down-stream communication bandwidth without a use of an up-stream communication bandwidth.

0086As described above, the down-stream communication bandwidth varies in accordance with acquisition of a voice and data transmission right. Therefore, a minimum communication bandwidth is determined as a bandwidth for data transmission by comparing an up-stream communication bandwidth of the terminal having the data transmission right, the down-stream communication bandwidth of the terminal using voice, and a value for the bandwidth obtained by subtracting the bandwidth required for reception of voice data from the down-stream communication bandwidth of the terminal not having a right for voice and data transmission (8070 of <figref idref="f0007">Fig. 8</figref>).

0087When any of the terminals 2T participating in the conference room does not have a voice transmission right (No in 8040 of <figref idref="f0007">Fig. 8</figref>), a bandwidth of the data transmission is determined in the following example sequence.

0088The minimum down-stream communication bandwidth among the down-stream communication bandwidths of the terminals 2T having no data transmission right participating in the conference room is compared with the up-stream communication bandwidth of the terminal having a data transmission right. When the minimum down-stream communication bandwidth is greater, the value of the up-stream communication bandwidth of the relevant terminal is calculated as the transmission bandwidth for data transmission. When the transmission bandwidth of the terminal having the data transmission right is greater, the value of the minimum down-stream communication bandwidth is calculated as the transmission bandwidth for data transmission (8080 of <figref idref="f0007">Fig. 8</figref>).

0089The data other than the voice data is transmitted to the server 2S on the basis of the transmission bandwidth determined by the above sequence (8090 of <figref idref="f0007">Fig. 8</figref>).

0090The data other than the voice data transmitted is transmitted via the server 2S to the other terminals 2T participating in the conference room in the communication bandwidth determined in the terminal side.

0091The PTT processing unit 101 supervises whether data transmission has been completed. If data transmission is not yet completed (No in 8200 of <figref idref="f0007">Fig. 8</figref>), whether a use of voice has changed is verified. When the use of voice has changed (Yes in 8300 of <figref idref="f0007">Fig. 8</figref>), the value of the communication bandwidth is reviewed by returning to operation 8040 and the data is subsequently transmitted with the reviewed communication bandwidth in operation 8090. Accordingly, since a value of the communication bandwidth for distribution of data may be changed in accordance with change of use of voice, the transmission rate of the data other than the voice data can be changed in accordance with change in the amount of voice data transmitted and received.

0092For example, when voice data is acquired and the data other than the voice data is transmitted during transmission of the voice data, the data other than the voice data is distributed at the beginning with the small communication bandwidth. However, when the voice is lost, the transmission rate of data can be raised by increasing the communication bandwidth. On the other hand, since only the data other than the voice data is transmitted at the beginning, such data has been transmitted with the available maximum communication bandwidth. However, if voice data is acquired during transmission of the data and thereby the voice data is distributed, the communication bandwidth for data distribution is changed to a value obtained by subtracting a value of a bandwidth for the voice data.

0093Therefore, since the data is subsequently distributed by changing the communication bandwidth to a smaller value, the communication bandwidth for distribution of voice data is acquired with a priority given for distribution of the voice data that is generated non-periodically regardless of the existence of distribution of data other than the voice data. Accordingly, broadcast communication are realized without deterioration of the quality of voice data. The operations from 8200 to 8300 are examples and added as required, and these functions are not essential functions.

0094According to a second embodiment of the present invention, an example of a control in the server side for the communication bandwidth for transmission of data other than the voice data will be described.

0095<figref idref="f0010">Fig. 11</figref> is a block diagram illustrating a second embodiment.

0096A server 3S for controlling the broadcast communication among a plurality of terminals and a plurality of terminals 3T1, 3T2, 3T3, 3T4, ...(hereinafter a terminal is generally called a "terminal 3T" in some cases) are provided for communications via various networks 3N1, 3N2, . ... hereinafter a network is generally called a "network 3N" in some cases). For example, it is assumed that a network 3N1 is a cellular phone communication network provided by the cellular phone company A and the communication system is a CDMA 1x system, while the network 3N2 is the cellular phone communication network provided by the cellular phone company B and the communication system is the PHS system. The network 2N3 is a wired network such as a LAN (Local Area Network). The server 3S for management of the broadcast communication is connected with the networks 3N1, 3N2, ... via the LAN.

0097The server 3S is further provided with a down-stream bandwidth storage unit 107, a distributing data transmitting rate control unit 106, and a distribution data storage unit 105, in addition to those described for server 1 S. The down-stream bandwidth storage unit 107 acquires and stores information of the communication bandwidth of the terminals 3T participating in the conference room. The distributing data transmitting rate control unit 106 determines when any of the terminals 3T transmits the data, the communication rate for each terminal 3T for distribution of data to the other terminals 3T. The distribution data storage unit 105 stores the data transmitted from the terminal 3T corresponding to the data transmitting terminal 3T for each conference room. Moreover, the terminal 3T is further provided with the distributing data transmitting rate control unit 202 in addition to the functions of the terminals 1T described above.

0098The PTT processing unit 101 collects the values of communication bandwidths to be used in the terminal 3T of the users who can participate to the PTT system and stores the values corresponding to the terminals 3T (1201 of <figref idref="f0011">Fig. 12</figref>). An example of the down-stream bandwidth storage unit 107 is illustrated in <figref idref="f0012">Fig. 13</figref>. The down-stream bandwidth storage unit 107 includes a participant 131 and down-stream bandwidth 132. The user ID of the participant participating in the conference room is set in participant information 131. A value of the down-stream communication bandwidth of the terminal 3T of the participant is set in the down-stream bandwidth 132. Collection of values of the down-stream communication bandwidths may be realized when a terminal has registered an application of the PTT system, or whenever participation is conducted in the conference room of the PTT system, or whenever a terminal has acquired voice and data transmission rights, or when the data received from a terminal is distributed to the other terminals.

0099When the communication bandwidth to be used by the terminal changes in accordance with the condition of the communication network, the communication bandwidth can be controlled in accordance with a change in the condition of the communication network by collecting the information of the communication bandwidth which can be used by each terminal particularly when the voice and data transmission rights can be acquired or when the data is distributed to each terminal. Moreover, the down-stream bandwidth storage unit 107 may be formed independently or may be administrated by providing an data to a user management unit 310 and a PTT management unit 110.

0100An example of transmission of pictures by a terminal 3T1 (user:horio) by participating in the conference room (conference room ID:PoCSes001) will be described. A display format (<figref idref="f0014">Fig. 15</figref>) for taking pictures is displayed on the terminal 3T1, requesting the user action. The user action for photography is similar to that in the example first embodiment. Moreover, in the example of <figref idref="f0014">Fig. 15</figref>, transmitting destination and priority may be designated at the time of transmitting the data other than the voice data. When a partner selecting button BT92 is selected, the transmitting destination can be designated. As the transmitting destination, for example, designation is possible to transmit the data to all members of the conference room or of participants or to transmit the data to a part of the members of the conference and the participants thereto. In the case where the data is transmitted to a part of the members and participants of the conference, the user IDs of the members as the transmitting destination and the participants are designated. When a priority button BT93 is selected, the priority can be designated. As the priority, the priority of data distribution is designated and a priority level is set allowing discrimination thereof.

0101The distributing data transmitting rate control unit 202 determines the transmission bandwidth of data when the relevant terminal 3T transmits the data other than the voice data. When the data transmitting operation is performed at the terminal 3T, whether the terminal 3T has acquired the voice is verified by referring to the voice recording unit 206. If the voice is acquired, the bandwidth obtained by subtracting the bandwidth required for transmission of voice data from the minimum guarantee bandwidth of up-stream of the terminal 3T is set as the communication bandwidth for transmission of data. If voice is not acquired, the minimum guarantee bandwidth of up-stream of the terminal is set as the communication bandwidth for transmission of data. In this example, the upper limit of the communication bandwidth of the terminal 3T is set as the minimum guaranteed bandwidth and the bandwidth required for voice data is subtracted from the minimum guaranteed bandwidth.

0102However, it is also possible to subtract the bandwidth required for voice data with reference to the communication bandwidth which may be used by the terminal 3T in place of the minimum guaranteed bandwidth. In this case, since not only voice data and the data other than the voice data, but also control data for the broadcast communication system and the control data for communication network, are transmitted and received, the communication bandwidth for such control data must also be considered. When both the minimum guaranteed bandwidth and the communication bandwidth which may be used by the terminal 3T are used for transmission and reception of voice data and the data other than the voice data, the communication bandwidth of the control data is not guaranteed probably resulting in delay of the control data. However, for effective application of the communication bandwidth, in some cases a communication bandwidth of the terminal 3T which is generally larger than the minimum guarantee bandwidth is used. It is also possible to vary a reference communication bandwidth. For example, a minimum guaranteed bandwidth is used in accordance with amount of data to be transmitted, and the communication bandwidth which may be used by the terminal 3T is set as the reference bandwidth, or selected through a switching operation. Such variations may be applied in the other example embodiments.

0103The data other than the voice data is transmitted to the server 3S in the communication bandwidth determined as described above.

0104The server 3S stores, upon reception of the data other than the voice data transmitted from the terminal 3T (12020 of <figref idref="f0011">Fig. 12</figref>), this data to the distribution data storage unit 105 corresponding to the identifiers of the terminals (12030 of <figref idref="f0011">Fig. 12</figref>). When the transmitting destination and priority of data are transmitted together with the data other than the voice data transmitted from the terminal 3T, these information pieces are also stored corresponding to the data. <figref idref="f0013">Fig. 14</figref> illustrates an example of the distribution data storage unit 105. The distribution data storage unit 105 includes a conference room ID 141, a transmitting source user 142, a transmitting destination user 143, a priority 144, a class of data 145, a capacity 146, and a content 147. The conference room ID to which the data has been transmitted is set in the conference room ID 141. The user ID of the terminal 3T having transmitted the data is set transmitting source user 142. The user ID of the transmitting destination designated at the time of transmission of the data or the information indicating that members of the conference room are all object of distribution is set transmitting destination user 143. The priority designated at the time of transmission of data is set in priority 144. A class of data or a class of file transmitted from the terminal 3T is set in item of class of data 145. A capacity of data transmitted from the terminal 3T is set capacity 146. A content of data transmitted from the terminal 3T or address of storing destination of the storage unit of the server 3S is set in content 147,.

0105For the control of distribution data in the server 3S, the data transmission right is not required to be limited only to one terminal. Even during the data transmission of the other terminals, data transmission can be realized to the terminals which are requesting the data transmission.

0106In the example of <figref idref="f0013">Fig. 14</figref>, distribution data is stored in the conference room having the conference room ID:PoCSes001. The first data is the data in which the transmitting source user 142 has the user ID:horio@fujipoc.com. The transmitting destination of this data is "all members of participants of the conference room" and the priority 144 is designated as "Usual". The class of data 145 is "JPEG", capacity of data 146 is "1MB", content of data 147 is stored in the file name "ABC.JPEG". The second data is the data in which the transmitting source user 142 has the user ID:okuyama@fujipoc.com. As the transmitting destination of this data 143, only the "user ID:ohno@fujipoc.com" is designated. Priority 144 is "Urgent". The class of data 145 is "IM-MSG", capacity 146 is "1KB", and content of data 147 is "Please call me later" which is the content of the message being stored.

0107When a plurality of data of the same conference room is stored in the distribution data storage unit 105 (Yes in 12040 of <figref idref="f0011">Fig. 12</figref>), the data distribution sequence is judged (12050 of <figref idref="f0011">Fig. 12</figref>). A determination is conducted, for example, with the following example operations: <ol id="ol0001"><li>a) Data having higher priority is selected on the basis of the priority designated when the data is transmitted from the terminal.</li><li>b) Data having the least capacity is selected by comparing the capacity of data.</li><li>c) Data for the greatest number of users is designated as the distributing destination is selected.</li><li>d) Data having higher priority is selected by judging the priority level through combination of above conditions is selected.</li></ol>

0108When the data as the distribution object is determined, a transmitting destination 143 stored corresponding to the data is acquired (12060 of <figref idref="f0011">Fig. 12</figref>).

0109Moreover, the communication bandwidth for transmission of data is determined in the following example sequence.

0110Whether any of participants of the conference room has acquired the voice in the conference room as the object is verified. When the data transmitting destination is designated to a part of the participants in place of all members of participants in the conference room, the user ID of the transmitting destination is identified by referring to the transmitting destination user 143 stored in the distribution data storage unit 105 and the following determination is made for the identified user ID.

0111When the voice is acquired (Yes in 12070 of <figref idref="f0011">Fig. 12</figref>), the minimum guaranteed bandwidths down-stream are all set as the transmission bandwidth of data for the terminal having acquired the voice, while the value obtained by subtracting the bandwidth for receiving the voice data from the minimum guaranteed bandwidth of down-stream is set as the transmission bandwidth for terminals which don't have voice (12080 of <figref idref="f0011">Fig. 12</figref>). If the voice is not acquired (No in 12070 of <figref idref="f0011">Fig. 12</figref>), the minimum guaranteed bandwidth of down-stream of each terminal is set as the transmission bandwidth of data (12090 of <figref idref="f0011">Fig. 12</figref>).

0112Data is distributed to each terminal on the basis of the transmission bandwidth being set for each terminal 3T (12100 of <figref idref="f0011">Fig. 12</figref>). Accordingly, even if the communication bandwidth of terminal 3T is different, data is distributed in accordance with the communication bandwidth of each terminal 3T

0113The PTT processing unit 101 supervises whether the data distribution has been completed. If data distribution is not yet completed (No in 12110 of <figref idref="f0011">Fig. 12</figref>), whether the voice has been changed is verified. When the voice is changed (Yes in 12120 of <figref idref="f0011">Fig. 12</figref>), the communication bandwidth is reviewed by returning to operation 12070. In operation 12110, the data is transmitted subsequently with the reviewed communication bandwidth. Accordingly, since the value of communication bandwidth for distribution of data may be changed in accordance with change in the voice, the transmission rate of the data other than the voice data can be changed in accordance with change in the amount of transmission and reception of the voice data. For example, when voice is acquired and the data other than the voice data is transmitted during transmission of the voice data, the data other than the voice data is distributed with a lower communication bandwidth at the beginning. However, if the voice is lost completely, the data transmission rate may be raised with expansion of the communication bandwidth. Since only the data other than the voice data has been transmitted at the beginning, the data has been transmitted in the maximum communication bandwidth in the usable bandwidths.

0114However, if the voice is acquired during transmission of data and the voice data is also distributed, the communication bandwidth for data distribution is changed to a value obtained by subtracting the bandwidth for voice data. Therefore, since the data is subsequently distributed by changing the communication bandwidth to a smaller value, the communication bandwidth for distribution of voice data is acquired with priority for distribution of voice data, which is generated non-periodically, without relation to distribution of data other than the voice data. Thus, broadcast communications may be realized without a decrease in the quality of voice data. The operations 12110-12120 may adding additional functions as required.

0115The first example embodiment describes an example in which the voice data is distributed to all terminals participating in the conference room and only the data other than the voice data is distributed to some of the terminals. In the third example embodiment, however, an example of transmitting the voice data to some of the terminals will be described.

0116The third example embodiment describes an example of controlling the communication bandwidth for transmission of the data for terminal 2T as in the case of the first embodiment.

0117The system structure of the third example embodiment is assumed to be identical to the system structure of the first embodiment illustrated in <figref idref="f0006">Fig. 7</figref>. Moreover, it is also assumed that the broadcast communication by four parties may be conducted after the terminal 2T1 (user:horio) designates three parties of the terminal 2T2 (user:ohno), terminal 2T3 (user:okuyama) and terminal (user:ikeda).

0118An example flow of the processes of the broadcast communication system from operation 2010-2073 of <figref idref="f0002">Fig. 2</figref> is identical to that up to the operations 2110-2120 and from operations 2800-2820. The processes different from that illustrated in <figref idref="f0002">Fig. 2</figref> (operations 2080, 2090, 2100, 2130) will be described with reference to <figref idref="f0015">Fig. 16</figref>.

0119The display format of a list of the names of four members including the user of a terminal 2T1 is displayed on the terminal 2T1. When the terminal 2T1 issues a request for the voice, the user of the terminal 2T1 identifies partners for sending the speech and selects the voice acquisition button BT41 on the display format (<figref idref="f0016">Fig. 17</figref>) displayed from the user interface unit 204. In this example, only the member of the display name:ohno among the four members is selected as the partner for sending the speech. The user interface unit 204 of the terminal 2T transmits the information indicating that the voice acquisition button BT41 is selected and the user ID of the selected member to the PTT processing unit 201. The PTT processing unit 201 generates a voice acquisition request command on the basis of the information received from the user interface unit 204 and sends this command to the server 2S via the IP communication unit 200.

0120The PTT processing unit 101 of the server 2S determines, upon reception of the voice acquisition request command from the terminal 2T via the IP communication unit 100 (Yes in 16010 of <figref idref="f0015">Fig. 16</figref>), whether the terminal 2T having acquired the voice exists by referring to the PTT management unit 110 (16020 of <figref idref="f0015">Fig. 16</figref>). When the command received from the terminal 2T is not the voice acquiring request command (No in 16010 of <figref idref="f0015">Fig. 16</figref>), the process shifts to the operation 2800 of <figref idref="f0002">Fig. 2</figref>.

0121An example of the PTT management unit 110 in this embodiment is illustrated in <figref idref="f0019">Fig. 21</figref>. In this embodiment, voice information 64 further includes voice owner 65 and partner information 66. In voice owner information65, the user ID of the user having acquired the voice is set and in the partner information 66, the user ID of the user designated with the voice acquiring request command is set.

0122When the terminal 2T having acquired voice exists (Yes in 16020 of <figref idref="f0015">Fig. 16</figref>), whether the user ID of the terminal 2T of the partner designated in the voice acquiring request command is already registered to the partner 66 of the terminal 2T having the voice is verified by referring to the PTT management unit 110.

0123When the user ID is already registered to the partner 66 (Yes, in 16030 of <figref idref="f0015">Fig. 16</figref>), the request for the voice is rejected and it is notified to the requesting terminal 2T (16050 of <figref idref="f0015">Fig. 16</figref>). If the user ID is not registered to the partner 66 (Yes in 16030 of <figref idref="f0015">Fig. 16</figref>), the voice is given, it is registered to the PTT management unit 110, and acquisition of the voice is notified to the requesting terminal 2T (16040 of <figref idref="f0015">Fig. 16</figref>).

0124When the terminal 2T having the voice does not exist (No. in 16020 of <figref idref="f0015">Fig. 16</figref>), the voice is given, it is then registered to the PTT management unit 110, and acquisition of the voice is notified to the requesting terminal 2T. Moreover, the user ID of the terminal 2T having acquired the voice and the user ID as the partner are notified to the other terminals 2T participating to the conference room (16040 of <figref idref="f0015">Fig. 16</figref>). In this timing, the terminal 2T registers, upon reception of these user ID having acquired the voice and the user ID as the partner of speech, these information pieces received to the voice recording unit 206. An example of the voice recording unit 206 in this embodiment is illustrated in <figref idref="f0016">Fig. 18</figref>. The voice recording unit 206 in this embodiment includes voice owner 181 and partner 182. To the voice owner 181, the user ID of the terminal having acquired the voice is set and to the partner 182, the user ID of the terminal 2T as the partner of speech is set.

0125In the example of <figref idref="f0016">Fig. 17</figref>, horio (user ID:horio@fujiPoC.com) selects ohno (user ID:ohno@fujiPoC.com) to request the voice. An example of the PTT management unit 110 of <figref idref="f0019">Fig. 21</figref> illustrates a condition after the voice of horio is recognized and is then registered. In the timing where horio requests the voice, okuyama (user ID:okuyama@fujipoc.com) is registered as the voice owner 65, while ikeda (user ID:ikeda@fujipoc.com) as the partner 66 to the item of the voice 64. Horio (user ID:horio@fujipoc.com) requesting the voice is not yet registered to the voice owner 65 of the voice 64 of the PTT management unit 110 and ohno (user ID:ohno@fujipoc.com) designated as the partner is not registered to the partner 66. Therefore, the voice is given, it is registered to the PTT management unit 110, and notified that horio (user ID:horio@fujipoc.com) has acquired the voice. Moreover, the user ID of the terminal having acquired the voice and the user ID of the terminal having been designated as the partner of speech are identified to the other terminals 2T participating to the same conference room. The terminals 2T having received the notification respectively register the newly notified user ID:horio@ fujipoc.com having acquired the voice and the user ID:ohno@fujipoc.com designated as the partner to the voice recording unit 206 (<figref idref="f0016">Fig. 18</figref>).

0126In above description, an example is given in which the voice is given to a plurality of users so long as the partners overlap, but it is also possible that the voice is given only to one terminal 2T, as in the example first embodiment.

0127After completion of the voice acquiring process, the process shifts to operation 2110 illustrated in <figref idref="f0002">Fig. 2</figref>.

0128Next, an example flow of processes for controlling communication bandwidth in an example the third embodiment will be described with reference to <figref idref="f0017">Fig. 19</figref>. Procedures after the terminal 2T has requested the data transmission right will be described.

0129The terminal 2T conducts the following determination for the other terminals participating in the same conference room so as to calculate a value that may be used in reception of the data with the down-stream communication bandwidth of respective terminals 2T

0130The terminal 2T determines whether the data transmission right has been acquired. When the data transmission right is acquired (Yes in 19010 illustrated in <figref idref="f0017">Fig. 19</figref>), a communication bandwidth for transmission of data is calculated using the following example procedures for each terminal 2T designated as a partner in the data transmission.

0131Whether the terminal 2T, as the partner of the data transmission, is registered as the partner 182 of voice is determined referring to the voice storage unit 206 (<figref idref="f0016">Fig. 18</figref>). When the terminal 2T is registered as the partner 182 of the voice (Yes in 19020 of <figref idref="f0017">Fig. 19</figref>), the relevant terminal 2T calculates, in order to receive both voice data and the other data, a value, obtained by subtracting the communication bandwidth required for reception of the voice data from the communication bandwidth which the relevant terminal 2T can use, as an down-stream communication bandwidth of the relevant terminal 2T (19030 of <figref idref="f0017">Fig. 19</figref>). When the terminal is not registered as the partner of the voice (No in 19020 of <figref idref="f0017">Fig. 19</figref>), the relevant terminal 2T sets, to receive only the data other than voice, the communication bandwidth which the relevant terminal 2T can use as the down-stream communication bandwidth of the terminal 2T (19040 of <figref idref="f0013">Fig. 14</figref>).

0132If the calculation of communication bandwidths that may be used for data transmission is not completed for all terminals 2T designated as partners of the data transmission (Operation 19050 of <figref idref="f0017">Fig. 19</figref>), the operations are repeated from operation 19020.

0133When the calculation of the communication bandwidth used for data transmission is completed for all terminals 2T that are designated as partners of data transmission (Yes in Operation 19050 of <figref idref="f0017">Fig. 19</figref>), a minimum value of the calculated communication bandwidths, for a terminal 2T as a partner of data transmission, is extracted (Operation 19060 of <figref idref="f0017">Fig. 19</figref>).

0134Moreover, when the terminal 2T having acquired the data transmission right is verified to have also acquired voice, a value obtained by subtracting the bandwidth of the voice data from an available up-stream communication bandwidth, which the relevant terminal 2T can use, is set as a useable-stream communication bandwidth. When the terminal 2T is verified not to have voice data, the useable up-stream communication bandwidth which the relevant terminal 2T can use is set as available up-stream communication bandwidth (Operation 19070 of <figref idref="f0017">Fig. 19</figref>).

0135The calculated minimum down-stream communication bandwidth of each terminal 2T is compared with the calculated up-stream communication bandwidth of the terminal 2T having acquired the data transmission right.

0136When the calculated minimum value of the down-stream communication enabling bandwidth of each terminal 2T is less than the calculated up-stream communication enabling bandwidth of the terminal 2T having acquired the data transmission right (Yes in operation 190080 of <figref idref="f0017">Fig. 19</figref>), the calculated minimum down-stream communication bandwidth of each terminal 2T is set as the usable communication bandwidth for data transmission (operation 19090 of <figref idref="f0017">Fig. 19</figref>). When the calculated up-stream communication enabling bandwidth of the terminal 2T having acquired the data transmission right is less than the calculated minimum down-stream communication bandwidth of each terminal 2T (operation 19080 of <figref idref="f0017">Fig. 19</figref>), a value of the calculated up-stream communication enabling bandwidth of the terminal 2T having acquired the data transmission right is set as the useable communication bandwidth for data transmission (operation 19100 of <figref idref="f0017">Fig. 19</figref>).

0137The data is transmitted to the terminal 2T designated as the partner of the data transmission with the useable communication bandwidth set by the operations described above (operation 9110 of <figref idref="f0017">Fig. 19</figref>).

0138In this example embodiment, change in the communication bandwidth during data transmission is not illustrated, but it is possible to add operations so as to dynamically change the communication bandwidth for transmission of data by monitoring a change in a setting of the voice as in the case of the example first embodiment.

0139Accordingly, even when a destination of voice data transmitted from the terminal 2T having acquired the voice and destination of other data transmitted from the terminal 2T having the data transmission right are only part of the members of the conference room and participants, the communication bandwidth for data transmission can be set in accordance with the voice data and the other data receiving conditions of the terminals 2T.

0140According to an example fourth embodiment of the present invention, voice data can also be transmitted to some of the terminals.

0141As in the case of the example second embodiment, an example of controlling the communication bandwidth for transmission of data in the side of server 3S is illustrated.

0142A system structure of the fourth embodiment is similar to that illustrated in <figref idref="f0010">Fig. 11</figref>. As in the example third embodiment, the terminal 3T1 (user:horio) designates three partners of terminal 3T2 (user:ohno), terminal 3T3 (user:okuyama) and terminal 3T4 (user:ikeda) to enable the broadcast communication by four parties with the procedures described in the third embodiment under the condition of the PTT management unit 110 of <figref idref="f0018">Fig. 20</figref>.

0143Flow of processes for controlling the communication bandwidth with the server 3S in this embodiment will be described with reference to <figref idref="f0018">Fig. 20</figref>. In <figref idref="f0018">Fig. 20</figref>, the processes after collection of the down-stream communication bandwidths of the terminal 3S are described.

0144The processes from operations 20020 to 20050 are similar to those in operations 12020 to 12050, and a similar description is omitted here.

0145In the priority judgment(20050), the terminal 3T as the distribution destination for the data as the transmission object is identified (20060 of <figref idref="f0018">Fig. 20</figref>) and the communication bandwidth for data transmission is calculated for each terminal 3T.

0146Whether the terminal 3T as a partner of data transmission is registered as a partner 66 of the voice transmission is verified by referring to the PTT management unit 110. Upon designation as the partner of the voice (Yes in operation 20070 of <figref idref="f0018">Fig. 20</figref>), the server 3S sets a value obtained by subtracting the bandwidth required for voice data from the down-stream communication bandwidth which the relevant terminal 3T can use as the useable communication bandwidth for transmission of data to the terminal 3T since the relevant terminal 3T receives both the voice data and the other data (operation 200080 of <figref idref="f0018">Fig. 20</figref>). When not registered as a partner of the voice transmission (No in operation 20070 of <figref idref="f0018">Fig. 20</figref>), the relevant terminal 3T sets a value for a down-stream communication bandwidth which the relevant terminal 3T can use as the available communication bandwidth for data transmission since the relevant terminal 3T receives only the data (operation 20090 of <figref idref="f0018">Fig. 20</figref>).

0147If calculation of the communication bandwidth used for data transmission is not completed for all terminals 3T designated as the partners of the data transmission (No in operation 20100 of <figref idref="f0018">Fig. 20</figref>), the processes of the terminal 3T not completed in the calculation are repeated continued by returning to the operation 20070.

0148When the communication bandwidth used for data transmission is determined for all terminals 3T designated as the partners of the data transmission (Yes in operation 20100 of <figref idref="f0018">Fig. 20</figref>), the data is transmitted with the calculated or preset communication bandwidth for each terminal 3T (20110 of <figref idref="f0018">Fig. 20</figref>).

0149The operations 20120 to 20130 are similar to those in operations 12110-12120 and the similar description is omitted here. These steps can be executed as required as in the case of second embodiment and are not always required.

0150As described above, a broadcast communication system which enables transmission and reception of voice data and the other data without deterioration in the quality of voice data is realized by controlling the communication bandwidth for distribution of the voice data and the other data in accordance with whether the broadcast communication by voice data is performed. Moreover, when the server controls the communication bandwidth for data distribution, the communication bandwidth is controlled in accordance with the conditions of communication of the terminals for each terminal. Accordingly, if the communication bandwidths of the terminals participating in conference room are different, the communication is removed of the influence of the terminals having lower communication bandwidths.

0151In the above example embodiment, an example of the transmission and reception of the voice data and the other data is described. Additional embodiments of the present invention include quality improvements in transmission of both picture data and the data other than the picture data. Further, embodiments of the present invention may be executed by computer instructions stored in a computer storage.

0152Moreover, in above embodiments, only the functions regarding the broadcast communication system are described for a server and terminals. However, the server and terminals may be used in combination with the other functions.

0153Although a few embodiments of the present invention have been shown and described, it would be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles of the invention, the scope of which is defined in the claims and their equivalents.

0154Embodiments of the present invention may be implemented in hardware, or as software modules running on one or more processors, or on a combination thereof. The invention may also be embodied as one or more device or apparatus programs (computer programs and computer program products) for carrying out part or all of any of the methods described herein. Such computer programs embodying the present invention may be stored on computer-readable media, or could, for example, be in the form of one or more signals. Such signals may be data signals downloadable from an Internet website, or provided on a carrier signal, or in any other form.

0155This application claims the benefit of <patcit id="pcit0001" dnum="JP2004256066A"><text>Japanese Patent Application No. 2004-256066</text></patcit>, filed on September 2, 2004 in the Japanese Patent Office.