System, method and multipoint control unit for multipoint multimedia conferencing

A multipoint control system for providing real-time multipoint conferencing among a plurality of conferencing terminal units wherein the conferencing is performed utilizing digital audio signals that are mixed a predetermined number of times in accordance with a predetermined mixing algorithm, said system comprising:

• a first multipoint control unit for transceiving digital audio signals using predetermined protocols for full-duplex communication to/from at least a first conferencing terminal and at least a second multipoint control unit, wherein said full-duplex communication comprises at least an exchange of digital audio signals;
• and
• at least the second multipoint control unit, operably coupled to at least a second conferencing terminal unit, for full-duplex communication with at least the first multipoint control unit, wherein the full-duplex communication further includes an exchange of control information, wherein the control information indicates whether an accompanying signal may be mixed;
• wherein each multipoint control unit comprises a processor that comprises:
• an audio signal selector for receiving a set of all digital audio signals from the multipoint control units and selecting digital audio signals to be transmitted to other multipoint control units, wherein said selecting is made in accordance with a predetermined selection algorithm using the control information received from other conferencing terminal units;
• and
• an audio mixer, operably coupled to the audio signal selector, for utilizing a predetermined mixing algorithm for mixing the selected digital audio signals when more than one digital audio signal is selected and for generating control information to indicate whether a resultant digital audio signal may be mixed again.

A multipoint conferencing control system for providing real-time multipoint conferencing from frames of audio input among a plurality of conferencing terminal units using predetermined protocols for full-duplex communication wherein the conferencing is performed utilizing digital audio signals that are mixed a predetermined number of times in accordance with a predetermined mixing algorithm and transmitted as frames, said system comprising:

• the plurality of operably coupled multipoint control units to which at least a first local terminal is operably coupled, wherein:
• for inbound direction audio processing:
• each conferencing terminal unit is utilized for determining a speech level for each frame of audio input from coupled local terminals,
• each conferencing terminal unit, excluding a conferencing terminal unit of a present speaker, is utilized for comparing a speech level of each frame of an inbound audio input received from neighboring conferencing terminal unit(s) with a speech level of a frame of audio input of coupled local terminals and transmitting frames from at least a first terminal with a highest speech level of audio input toward/to the conferencing terminal unit of a present speaker;
• and
• the conferencing terminal unit of the present speaker is utilized for transmiting the frames of audio input from at least the first terminal with a highest speech level of audio input to the local terminal of the present speaker, and
• for outbound direction audio processing:
• the conferencing terminal unit of the present speaker is utilized for transmiting, in accordance with a predetermined scheme, the frames of audio input comprising one of A-B:
• A) frames of audio input from the conferencing terminal unit of the present speaker, and
• B) frames of audio input from the conferencing terminal unit of the present speaker and at least the first terminal with a highest speech level of audio input, and
• for setting an outbound allow/disallow status bit to disallow where mixing has occurred and to allow where only audio input from the conferencing terminal unit of the present speaker is being transmitted,
• each conferencing terminal unit, excluding a conferencing terminal unit of a present speaker, is utilized for:
• where the outbound allow/disallow status bit is set to allow and inbound audio is louder than audio input from a local terminal, mixing the inbound audio with outbound audio and transmitting the mixed audio to the local terminal and where an inbound audio is weaker than audio input from a local terminal, mixing the local audio with outbound audio and transmitting the mixed audio to the link where the inbound audio is received and changing the outbound allow/disallow status bit to disallow, and
• where the outbound allow/disallow status bit is set to disallow, transmitting the outbound audio to the local terminal.