Method and apparatus for improving nuisance signals in audio/video conference

BACKGROUND

1.

Field of Invention

0001The present invention relates to the field of multipoint audio/video conferences, and more particularly to improving the quality of the conference by reducing nuisance signals.

2.

Description of Background Art

0002Multipoint conferences of audio and/or video and/or multimedia are a communication between more than two participants. Commonly, conference calls may be established over a communications network, such as the Public Switched Telephone Network ("PSTN"), Integrated Services Digital Network (ISDN), Internet Protocol (IP) network, etc. The network contains Multipoint Control Units (MCU) and/or audio bridges that route and compose the communications of the participants in the call. The operation of MCUs and audio bridges is well known to those skilled in the art. An exemplary audio bridge is depicted in US Patent application number 10/072,081 or in US Patent application number 10/144,561, the contents of which are incorporated herein by reference. It should be noted that the terms MCU and audio bridge may be used interchangeably herein.

0003A common MCU may receive audio signals from a plurality of conferees, analyze the signals and create control information such as, but not limited to, VAD (Voice Activity Detection), signal energy, and signal quality measures. Based on the control information, decisions may be made regarding whose signals will be mixed and distributed among the other conferees, or whose signal will be muted due to a conclusion that the signal is below acceptable quality. Un Acceptable Signal (UAS) is an objective criteria and may depend on the type of the conference. Exemplary criteria may be non-voice signals such as: music, DTMF, background noise, etc. The terms noisy signal, nuisance and UAS may be used interchangeably and the term nuisance may represent those terms.

0004There are known methods for generating information regarding signal energy, VAD and quality. Exemplary algorithms for creating this information are depicted in G723.1 (used in Annex A for the same standard); G729.1 Annex B: and GSM AMR (GSM 06.71) using the VAD algorithm GSM 06.94. A simple algorithm for Nuisance Detector (ND) may define nuisance when the signal energy (SE) is above a certain level, while the VAD indicates that the signal is not voice is ND=SE and (not VAD).

0005The quality of a conference depends on the automatic decisions of those methods. For example, a sensitive ND algorithm may disconnect a valid participant, while a less sensitive algorithm may add to the conference mix audio of a noisy connection. Conference mix is the composed audio signal of the selected conferees. The selection is based on the conference setup parameters and on automatic decisions based on analyzing the signals of the current speakers. There are cases where an automatic decision may frequently fail. For example, in the cases where a conferee places the conference call on hold and accepts another call, during the hold period a private branch exchange (PBX), through which the conferee is connected to, may play "music on hold over the connection to the conference, disturbing the rest of the participants. "Music on hold" may be music, broadcast radio, advertising or other signals to a party waiting on hold. Generally "Music on hold" may have the same properties as speech and therefore it may pass the criteria of common VAD and/or ND algorithms and may be transmitted to the other parties in the conference. On the other hand, a sensitive ND that is not tuned to the connection quality of a certain conferee may harm/disconnect a valid conferee. Therefore it is difficult to pre-tune the ND algorithm to different conferee's conditions.

0006Thus, it is evident that current technologies of automatic nuisance detection in audio/video conferencing may make the wrong decisions that reduce the quality of the conference. Therefore, there is a need in the art for a new nuisance detection method that may overcome these deficiencies.

SUMMARY OF THE INVENTION

0007Systems according to the present invention solve the above-described problem by providing a path to a conferee that has been defined as a source of nuisance by an automatic decision of the MCU to respond to this automatic decision and to correct or adjust/tune the ND according to his/her audio signal. The invention is defined in the independent claims 1, 15 and 28, respectively. Particular embodiments of the invention are set out in the dependend claims.

0008For example, in a telephone conference, in which at least one of the conferee may be connected to the conference via a PBX, the conferee may place the conference on 'HOLD' forcing a nuisance signal over the connection to the conference. Then the ND may identify this connection as a nuisance connection and send this indication to an exemplary control unit in the MCU. The control unit upon receiving an indication that the conferee channel is nuisance may mute the signal coming from this conferee. Then the exemplary controller may place an Interactive Voice Response (IVR) message over the audio signal toward the conferee. An exemplary message may inform the conferee that he has been muted and requesting the conferee to press one of the touch tone keys, for instance '1', if he just returns from 'HOLD,' to press '3' if the conferee using a noisy line/environment, or press '5' to disable the ND algorithm, etc.

0009If a response is not received, the message may continue for a certain period or for the rest of the conference. If one of those keys has been pushed the system according to the present invention may act as follows. If the key is '1' an exemplary embodiment of the present invention cancels the mute situation and enables the conferee to be heard. If the key is '3' the exemplary embodiment of the present invention may reduce the sensitivity of the ND algorithm. Then the control unit enables the conferee to be heard in the conference while keeping a record of this adjustment. If the new level is above this tolerance the exemplary controller may instruct the conferee that he is too noisy and refuses to add the conferee's audio to the conference. If the key is '5' the exemplary embodiment of the present invention may disable the ND algorithm and connects the nuisance conferee without condition.

0010Other exemplary embodiments may request, using an IVR message, from another conferee, for example the chairman of the conference, to decide whether to mute the noisy conferee or not.

0011Other exemplary embodiments may place a noisy conferee in push to talk (PTT) operation, instruct the noisy conferee, using an IVR message, to push momentarily any one of the keys each time he wishes to talk and to push again upon terminating his/her part.

0012In general, systems according to the present invention may use other than DTMF feedback means to respond, such as but not limited to: voice recognition, network control signals such as ISDN 'D' channel, control packets over IP communication, etc.

0013Thus, systems according to the present invention advantageously offer an improved algorithm that handles nuisances in conferences by requesting feedback from the nuisance conferees. The feedback from the noisy conferee may correct the automatic decision and therefore improve the quality of the conference.

0014Other features and advantages of the present invention will become apparent upon reading the following detailed description of the embodiments with the accompanying drawings and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

0015<ul id="ul0001" list-style="none" compact="compact"><li>FIG. 1A is a block diagram showing an exemplary conference environment;</li><li>FIG. 1B is a block diagram of an embodiment according to the invention, including a general description of an audio unit in an MCU;</li><li>FIG. 2A is a block diagram of an ND that operates according to an exemplary embodiment of the present invention; and</li><li>FIG. 2B is a flow diagram showing the steps of an exemplary method for handling of a nuisance participant.</li></ul>

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

0016Turning now to the figures in which like numerals represent like elements throughout the several views, exemplary embodiments of the present invention are described. For convenience, only some elements of the same group may be labeled with numerals. The purpose of the drawings is to describe exemplary embodiments and not for production. Therefore features shown in the figures are chosen for convenience and clarity of presentation only.

0017FIG. 1A is an exemplary block diagram illustrating a general description of a conference environment <b>100</b>. The conference environment may have endpoints <b>1110aa-nk,</b> operator <b>1115</b>, multimedia communications <b>1120aa-nk &amp; 1122a-k</b>, networks <b>1130a-k</b>, and Multimedia Conference Control Unit (MCCU) <b>1140</b>. In one exemplary embodiment, the MCCU <b>1140</b> may include at least one Network Interface (NI) <b>1142</b>, Compressed Audio Common Interface (CACI) <b>110</b>, audio unit <b>1160</b>, Management and Control System (MCS) <b>1170</b>, control signals <b>1174</b>, a host <b>1200</b>, and video unit <b>1300</b>. Other exemplary embodiments may not have a video section and may be used for audio conferences only. MCCU 1140 may handle a nuisance conferee by using embodiments according to the present invention.

0018The pluralities of endpoints <b>1110aa-nk</b> are connected via the plurality of networks <b>1130a-k</b> to the MCCU <b>1140</b>. The MCCU <b>1140</b> may be an MCU, or an audio only multipoint control unit (an audio bridge), for example. The MCCU <b>1140</b> and/or some or all of its components are logical units that may be implemented by hardware and/or software. The MCS <b>1170</b> may be a control module and may be a logical unit that controls the operation of the MCCU <b>1140</b>.

0019An endpoint is a terminal on a network, capable of providing one way or two-way audio and/or visual communication with other terminals or with the MCCU <b>1440</b>. The information communicated between the terminals and/or the MCCU <b>1440</b> may include control signals, indicators, audio information, video information, and data. A terminal may provide any combination of several different types of inputs and/or outputs, such as speech only, speech and data, a combination of speech and video, or a combination of speech, data, and video. In case of audio conference, the endpoint may be common telephone, cellular telephone etc.

0020The NI <b>1142</b> receives multimedia communications <b>1122a-k</b> via a plurality of networks <b>1130a-k</b> and multimedia communications <b>1120aa-nk</b> from the plurality of the endpoints <b>1110aa-nk</b>, and processes the media communication according to communication standards that are used by each type of network, such as, but not limited to, H.323, H.321, H.324, H.324M, SIP, and/or H.320 ISDN, PSTN etc. The NI <b>1142</b> then delivers compressed audio, compressed video, compressed data, and control streams to appropriate logical modules in the MCCU <b>1140</b>. Some communication standards require that the process of the NI <b>1142</b> include demultiplexing the incoming multimedia communication into compressed audio, compressed video, compressed data and control streams. In the opposite direction, the NI <b>1142</b> receives the separate streams from the various units (e.g., the MCS <b>1170</b>, audio unit <b>1160</b>, and/or video unit <b>1300</b>) and processes the streams according to the appropriate communication standard. The NI <b>1142</b> then transmits the streams to the appropriate network <b>1130a-k</b>.

0021The audio unit <b>1160</b> receives the compressed audio streams of the plurality of endpoints <b>1110aa-nk</b> via the NI <b>1142</b> and CACI <b>110</b>, processes the audio streams, mixes the relevant audio streams, and sends the compressed mixed signal via the Compressed Audio Common Interface (CACI) <b>110</b> and the NI <b>1142</b> to the endpoints <b>1110aa-nk</b>. Audio unit <b>1160</b> may be a logical unit and is described below in conjunction to Fig. 1B.

0022The video unit <b>1300</b> may be a logical unit that receives and sends compressed video streams. The video unit <b>1300</b> includes at least one video input module that handles an input portion of a video stream <b>1302</b> from a participating endpoint and at least one video output module that generates a composed compressed video output stream that is sent via Compressed Video Common Interface (CVCI) <b>1302</b> to NI <b>1142</b> and from there to the designated endpoints <b>1110aa-nk</b>. An exemplary operation of such a video unit is described in U.S. Patent Number U.S. 6,300,973, which is incorporated herein by reference. The video unit is not mandatory for the operation of the present invention. The present invention may be used by MCCU that do not have a video unit, such as an audio bridge.

0023Preferably, the host <b>1200</b> communicates with the operator <b>1115</b> of the MCCU <b>1140</b>, where the operator <b>1115</b> may have an operator's station for communicating with the host <b>1200</b>. The host <b>1200</b> controls the MCCU <b>1140</b> via the MCS <b>1170</b> according to instructions from the operator <b>1115</b>. However, the operator <b>1115</b> is not mandatory. The MCCU may operate automatically without operator.

0024FIG. 1B is an exemplary block diagram of an embodiment of a general audio unit <b>1160</b> using an embodiment of the present invention. The embodiment of <b>FIG. 1B</b> includes a Compressed Audio Common Interface (CACI) <b>110</b>, a control bus <b>135</b>, MCS <b>1170</b>, and audio unit <b>1160</b> having compressed signals <b>115</b> and <b>117</b>, codec <b>120</b>, decoded information <b>126</b>, mixed output <b>128</b>, Decoded Audio Common Interface (DACI) <b>140</b>, and bridge <b>150</b>. The codec <b>120</b> includes a decoder <b>122</b> and an encoder <b>124</b>, while the bridge <b>150</b> includes analyze and enhance (A&amp;E) units <b>152</b>, information signals <b>153</b>, control unit <b>154</b>, IVR unit <b>154a</b>, switch <b>156</b>, control signals <b>157</b>, selected signals <b>159</b>, mixer <b>160</b>, and mixed signals <b>161</b>.

0025FIG. 1B describes the flow of audio streams in one example of the present invention. Compressed audio streams, from all endpoints that are connected to an MCCU are transferred over the Compressed Audio Common Interface (CACI) <b>110</b>. The MCS <b>1170</b> may allocate a codec <b>120</b> to each one of the endpoints <b>1110aa-nk</b> (FIG. 1A).

0026Further, the CACI <b>110</b> carries signals to and from endpoints <b>1110aa-nk.</b> For example, the compressed signal <b>115</b> from one of the endpoints <b>1110aa-nk</b> is routed through the CACI <b>110</b> to the decoder <b>122</b> in the codec <b>120</b>, which was previously allocated to that endpoint by the MCS <b>1170</b> via control bus <b>135</b>. The decoder <b>122</b> may be a logical unit, software or hardware or a combination of those, and may decode a compressed audio stream, based on the communication standards such as, but not limited to G.711, G.723.1, G.728, G.729, MPEG or relay uncompressed audio. The decoder <b>122</b> then decodes the compressed audio stream, such as compressed signal <b>115</b>, and broadcasts the decoded signal <b>126</b> over the Decoded Audio Common Interface (DACI) <b>140</b>. The DACI <b>140</b> is a bus that may have broadcasting capabilities. The DACI <b>140</b> may be implemented for example by any one of or any combination of Time Division Multiplexing (TDM), Asynchronous Transmission Mode (ATM), Local Area Network (LAN), wireless technology, or shared memory. An appropriate bridge 150 may then grab the decoded signal from the DACI <b>140</b> and may analyze, enhance, and/or mix the decoded signal and return the output <b>161</b> to the DACI <b>140</b>.

0027The encoder <b>124</b> may be a logical unit. The encoder <b>124</b> may compress the output 128 of the appropriate bridge <b>150</b> forming a compressed audio stream, such as the compressed signal <b>117</b>, based on the communication standard such as, but not limited to G.71 1, G.723.1, G.728, G.729, and/or Motion Picture Expert Group (MPEG), transferred as decoded audio to an endpoint that receives decoded audio.

0028The MCS <b>1170</b> may use a database that holds the connection parameters (e.g., codecs and bridges, etc.) and the connection status (e.g., normal, mute etc.) of each endpoint (participant) that is currently connected to the MCCU, in every conference that is currently managed by the MCCU. The Mute (M) connection status may mean that the participant cannot be heard in the conference. The Normal (N) connection status may mean that the participant can be heard and can listen to the conference etc. According to the database, the MCS <b>1170</b> programs one or more bridges <b>150</b> to grab from the DACI <b>140</b> the decoded signals of all the participants associated with a conference that is assigned to those bridges <b>150</b>.

0029The decoded output <b>126</b> of any codec <b>120</b> can be grabbed by more than one bridge 150, allowing the participants to be associated with more than one conference. The decoded streams from the decoders <b>122</b> on the DACI <b>140</b> may be grabbed by the bridge <b>150</b> and then analyzed and enhanced by the analyze and enhance unit <b>152</b>. The analyze and enhance unit <b>152</b> may be a logical unit, and may include a set of algorithms for analyzing an audio stream of a participant and/or enhancing its quality, such as, but not limited to, International Telecommunications Union (ITU) G.165 (echo canceling), Dual Tone Multi-Frequency (DTMF) detection, DTMF suppression, and/or Voice Activity Detector (VAD), signal energy, and nuisance analysis.

0030The bridge <b>150</b> may have one or more analyze and enhance units <b>152</b>. Each analyze and enhance unit <b>152</b> is assigned to a single participant and is programmed according to the connection status of that participant in the conference. The control unit <b>154</b> controls a conference that receives all signals from the analyze and enhance unit <b>152</b> and selects the participants that will be routed via switch <b>156</b> to the mixer <b>160</b>. The control unit <b>154</b> may implement an exemplary method of the present invention for handling by utilizing the analysis signals <b>153</b> coming from analyze and enhance units <b>152</b> and controlling the IVR module <b>154a</b> and switch <b>156</b>. The exemplary method is described below in conjunction with FIGS. 2A &amp; 2B. A single bridge <b>150</b> may serve a conference, a group of conferees or a single conferee. In the last two cases more than one bridge <b>150</b> may be involved in the conference.

0031The mixer <b>160</b> receives the enhanced streams from all of the selected participants and/or the signal from IVR <b>154a</b> and supplies each participant with an uncompressed mixed audio stream of the selected participants and/or the signal IVR <b>154a</b>. Mixer <b>160</b> may supply more than one stream <b>161</b>, each stream having a different mix.

0032Signals <b>153</b> from the analyze and enhance unit <b>152</b> are sent to the control unit <b>154</b> and the enhanced decoded audio signals <b>155</b> are sent from the analyze and enhance units <b>152</b> to the switch unit <b>156</b>. The switch unit 156 is a selector that receives the decoded streams from all the participants in a conference as well as the IVR unit <b>154a</b> and transfers the selected streams to mixer <b>160</b>. The selection is based on the decisions of the control unit <b>154</b>. The decisions of the control unit <b>154</b> are based on received commands from the MCS <b>1170</b>, which define the connection status of the participants in the conference that is assigned to the bridge <b>150</b>, and the information signal <b>153</b> from the analyze and enhance unit <b>152</b>. The control unit <b>154</b> controls, via control signals 157, the switch <b>156</b>, and the mixer <b>160</b>. For example, in a case where a participant's connection status is Normal (N), the analyze and enhance unit <b>152</b> that is associated with that participant may indicate that the voice signal meets a certain criteria such as set forth by VAD, (e.g., such as the energy level being above a certain value.). Then, the control unit <b>154</b> via switch <b>156</b> selects the output <b>155</b> of the analyze and enhance unit 152, which is assigned to the participant, as one of the inputs to the mixer <b>160</b>.

0033In another case, when the analyze and enhance unit <b>152</b> that is associated with a participant may indicate to the control unit <b>154</b> that the participant signal is nuisance. The control unit <b>154</b> may initiate an exemplary embodiment of the present invention, as illustrated in FIG. 2A &amp; 2B. It may instruct the switch <b>156</b> to remove the audio signal <b>155</b> that belongs to this nuisance conferee from the mixer <b>160</b> of all the other participants, placing the nuisance conferee in Mute state. In parallel, the control unit <b>154</b> may instruct switch <b>156</b> to select the IVR <b>154a</b> output as the input to the mixer of the nuisance participant.

0034In an alternate embodiment (not shown in the drawings) the output of the IVR unit may be delivered directly to the DACI, the encoder of the nuisance conferee having been instructed to grab the IVR's signal from the DACI instead of the output of the appropriate mixer.

0035The mixer <b>160</b> mixes the selected audio signals to form the mixed signals 161, and broadcasts the mixed signals <b>161</b> over the DACI <b>140</b>. Some embodiments of the bridge 150 have the capability of eliminating the voice of a speaker from the mixed signal that is aimed to the endpoint of that speaker. Control unit <b>154</b> may update the MCS <b>1170</b> with the new situation of the nuisance conferee.

0036The MCS <b>1170</b>, based on the connection status stored in the database, commands one or more codecs <b>120</b> to grab the mixed output <b>128</b> from the DACI <b>140</b> for listening to the conference. After grabbing the mixed output <b>128</b> from the DACI <b>140</b>, the encoder <b>124</b> encodes the decoded signal from the appropriate bridge <b>150</b>, and sends the compressed signal <b>117</b> via the CACI <b>110</b> to the appropriate participant.

0037The codecs <b>120</b> and the bridges <b>150</b> may be implemented by Digital Signal Processors (DSPs) such as, but not limited to, Texas Instruments DSP, TMS320C31. One DSP can include more than one unit (e.g., more than one codec and/or bridge). In the above example, the codec 120 handles a single participant's audio signal, and the bridge 150 handles one conference or part of a conference.

0038Referring now to FIG. 2A, which is a block diagram of an exemplary embodiment, ND <b>2020</b> is an adjustable ND that may be part of the analyze and enhance unit <b>152</b> in FIG. 1B. In the exemplary embodiment each ND <b>2020</b> unit is associated with a single conferee. The ND <b>2020</b> uses a nuisance algorithm with a current set up and a current parameters set. The ND <b>2020</b> sends indications to control unit <b>154</b> (FIG. 1B). The control unit <b>154</b>, based on these indications and existing control information, reaches decisions <b>2025.</b> According to those decisions the control unit <b>154</b> sends control instructions that influence the audio stream to the appropriate conferee. The control instructions may be sent to the mixer <b>160</b> or to switch <b>156</b> (FIG. 1B). In parallel an IVR message <b>2040</b> may be sent to the nuisance conferee requesting feedback. Upon receiving feedback from the conferee the control unit tune/adjust the ND by updating its parameters.

0039FIG. 2B is a flowchart depicting an exemplary method 200 according to the present invention for handling a nuisance conferee by the exemplary control unit <b>154</b> (FIG. 1B). Upon receiving a ND indication from a certain A&amp;E unit <b>152</b>, control unit <b>154</b> starts <b>210</b> the nuisance handling task. First, in order to eliminate the nuisance from the rest of the participants, control unit <b>154</b> places <b>215</b> the nuisance participant into Mute state. The control unit <b>154</b> instructs switch <b>156</b> to prevent the audio signals <b>155</b> that belongs to this nuisance conferee from the appropriate mixer <b>160</b>.

0040Then the control unit instructs <b>224</b> the IVR <b>154a</b> to send a "Mute" message to the nuisance conferee. In parallel, as long as the IVR message is active, the switch <b>156</b> is instructed to select the input of the IVR unit <b>154a</b> as the only input to a mixer <b>160</b> that is associated with the nuisance conferee. An exemplary "Mute" message may be "Please be aware that you have been muted. Please press '1' upon returning from 'Hold'. Please press '3' if you were not in hold."

0041Other exemplary embodiments may offer other or additional options. For example, an additional option which may be added is one such as, but not limited, to "Please press '5' to disable the ND algorithm" etc.

0042At the end of the message the control unit may wait <b>226</b> for a period 'T1'. Period 'T1' may be in the range of a few hundreds of milliseconds up to several seconds. Exemplary values of 'T1' may be 800 milliseconds, 2 seconds etc. At the end of the waiting period, the control unit verifies <b>230</b> whether a DTMF signal as been identified by the A&amp;E unit 152 that is associated with the nuisance conferee. If no DTMF signal has been received, which may reflect that the nuisance conferee is not listening to the conference, then the control unit returns to step <b>224</b> and continues the mute decision. Such a case may happen if the nuisance conferee has put the conference call on hold or has been disconnected. In any of those cases no harm is made either to the nuisance conferee or to the rest of the participants. The loop comprising steps <b>224</b>, <b>226</b> and <b>230</b> may continue until a DTMF signal is received. If no DTMF signal is received or a DTMF signal other than '1' or '3' or '5' has been received, the loop may continue until the end of the conference. Other embodiments may add a counter that counts the number of cycles and may disconnect the nuisance conferee after a certain number of cycles.

0043In case a DTMF signal has been received and has been identified as '1,' which indicates that the nuisance conferee has returned to the conference and pushed the appropriate key, then control unit <b>154</b> (FIG. 1B) instructs <b>234</b> the appropriate switch <b>156</b> to enable the audio signal <b>155</b> associated with the nuisance conferee and to disconnect the IVR unit <b>154a</b> from the appropriate mixer. Then the task is terminated <b>236</b>.

0044In case a DTMF signal has been received and has been identified as the number indicating that the nuisance conferee is listening to the conference, the received ND indication may be due to a noisy connection or noisy environment. In the current example the number is '3'. Then, at step <b>238</b> the level of the threshold of the ND 2020 is increased. Increasing the threshold reduces the sensitivity to noise. The present invention may set the initial threshold level to a low level. Based on the feedback from a nuisance conferee, embodiments according to the present invention adjust the setup according to the current connection.

0045Different embodiments of the present invention may utilize different methods for increasing the threshold level. One exemplary method may increase the level by a certain percentage from the current level each time, 10%, 30%, and 50%, for example. Other methods may use a fixed value each time; other methods may change the values according to the value of a counter (Cnt.) etc. The Cnt. is reset during the initiation of the conference and the value of the Cnt. is increased by one <b>238</b> each time that the conferee has been identified as a nuisance.

0046At step <b>240</b> a decision is made whether the nuisance conferee is a disturbing one. If the nuisance conferee is defined as a disturbing conferee, the Mute state of the conferee will be kept for the rest of the conference. If not, the Mute state may be canceled. An exemplary embodiment may compare <b>240</b> the new ND level to a predefined maximum level, etc. Max. The Max value is a parameter that may be set during the set up of the conference or may be a default value above which the noise is disturbing and it is better to permanently mute the nuisance conferee. Other embodiments may make a decision based on the value of the Cnt. If the value is above a certain number of interactions, it indicates that the connection is a disturbing connection and the conferee may be defined as a disturbing conferee.

0047If the connection is not a disturbing connection <b>240,</b> for example, the ND level is below Max, then the mute state is canceled <b>234</b> and the task is terminated <b>236</b>. The task may be restarted if a new ND indication will be received. Then the task will start at step <b>210</b> but this time the value of the Cnt. will be other than zero.

0048If the connection is a disturbing connection <b>240</b>, for example, the ND level is above Max, then the exemplary embodiment of the present invention may keep the mute state of the nuisance conferee and allowing the nuisance conferee only to listen to the conference. At step <b>242</b> the IVR module <b>154a</b> (FIG. 1B) is instructed to send a "Disturbing" message. An example for the "Disturbing" message may be: "Please be aware that you have been muted. In case you want to speak, please dial in again."

0049Other embodiments may offer the conferee the option to disconnect the current connection and re-try again. Other embodiments may request human assistance to decide how to proceed with the nuisance conferee.

0050In case a DTMF signal has been received and has been identified as '5', this indicates that the nuisance conferee has requested to disable the ND 2020. Such a request may be done when the involvement of this conferee is crucial in this conference and he/she must be heard even though the connection is noisy. Then the control unit disables <b>232</b> the ND 2020 and cancels the mute condition of the nuisance conferee.

0051Alternate embodiments of the present invention may use other than DTMF feedback means to respond, such as but not limited to: Voice Recognition, network control signals such as ISDN 'D' channel, control packets over IP communication, etc.

0052The present invention may handle more that one nuisance conferee. For each nuisance conferee a dedicated task may be initiated.

0053In this application the words "unit" and "module" are used interchangeably. Anything designated as a unit or module may be a stand-alone unit or a specialized module. A unit or a module may be modular or have modular aspects allowing it to be easily removed and replaced with another similar unit or module. Each unit or module may be any one of, or any combination of, software, hardware, and/or firmware.

0054Overall, embodiments according to this invention will improve the quality of a conference by handling a nuisance conferee automatically with feedback from the nuisance conferee that improves the automatic decision. The process is transparent to the rest of the conferees.

0055In the description and claims of the present application, each of the verbs, "comprise" "include" and "have", and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of members, components, elements, or parts of the subject or subjects of the verb.

0056The present invention has been described using detailed descriptions of embodiments thereof that are provided by way of example and are not intended to limit the scope of the invention. The described embodiments comprise different features, not all of which are required in all embodiments of the invention. Some embodiments of the present invention utilize only some of the features or possible combinations of the features. Variations of embodiments of the present invention that are described and embodiments of the present invention comprising different combinations of features noted in the described embodiments will occur to persons of the art. The scope of the invention is limited only by the following claims.

Within the range of the invention there are the following inventive concepts:

0057A method for improving the quality of a conference of a plurality of conferees by handling nuisance conferees, the method comprising waiting for a nuisance indication that at least one of the conferees has been identified as a nuisance conferee; informing the at least one nuisance conferee about the nuisance indication and requesting a feedback indication; and waiting for the feedback indication. In an embodiment of the method the nuisance indication is detected in the audio stream. In another embodiment the method further comprises placing the at least one nuisance conferee in mute state upon receiving the nuisance indication.

0058In a further embodiment of the method the feedback indication indicates the at least one nuisance conferee has returned from hold, or the feedback indication indicates a noisy connection, or the feedback indication indicates to cancel nuisance detection. In another embodiment the method further comprises removing the mute state of the at least one nuisance conferee.

0059In a further embodiment the method further comprises increasing the nuisance detection level of the at least one nuisance conferee; and removing the mute state of the at least one nuisance conferee. Or determining if the nuisance detection level is above a predetermined level and maintaining the mute state of the at least one nuisance conferee if so.

0060In another embodiment the method further comprises requesting the at least one nuisance conferee to terminate and rejoin the conference.

0061In a further embodiment the method further comprises canceling nuisance detection of the at least one nuisance conferee; and removing the mute state of the at least one nuisance conferee.

0062In a still further embodiment the method further comprises determining, based on the nuisance conferee's feedback, whether the at least one nuisance conferee is a disturbing conferee and if the at least one nuisance conferee is not a disturbing conferee than the mute state is terminated or if the at least one nuisance conferee is a disturbing conferee than continuing the mute state.

0063In a further embodiment the method further comprises informing the disturbing conferee as having been defined as being a disturbing conferee and recommending redialing or informing the disturbing conferee as having been defined as being a disturbing conferee and recommending use of a push to talk function.

0064A first multipoint control unit for conducting and controlling at least one conference between a plurality of conferees, the multipoint control unit comprises a control unit wherein the control unit is adapted to: wait for a nuisance indication that at least one of the conferees has been identified as a nuisance conferee; place the at least one nuisance conferee in mute state; inform the at least one nuisance conferee about the mute state and request a feedback indication; and wait for the feedback indication. In an embodiment of the first multipoint control unit the nuisance indication is detected in the audio stream. In a further embodiment of the first multipoint control unit the feedback indication indicates the at least one nuisance conferee has returned from hold.

0065In another embodiment of the first multipoint control unit the control unit is further adapted to remove the mute state of the at least one nuisance conferee. In still another embodiment of the first multipoint control unit the feedback indication indicates increasing the nuisance detection level.

0066In a further embodiment of the first multipoint control unit the control unit is further adapted to increase the nuisance detection level of the at least one nuisance conferee; and remove the mute state of the at least one nuisance conferee. In another embodiment of the first multipoint control unit the control unit is further adapted to determine if the nuisance detection level is above a predetermined level and to maintain the mute state of the at least one nuisance conferee if so.

0067In a further embodiment of the first multipoint control unit the control unit is further adapted to request the at least one nuisance conferee to terminate and rejoin the conference. In another embodiment of the first multipoint control unit the feedback indication indicates to cancel nuisance detection.

0068In a further embodiment of the first multipoint control unit the control unit is further adapted to cancel nuisance detection of the at least one nuisance conferee; and remove the mute state of the at least one nuisance conferee. In a further embodiment of the first multipoint control unit the control unit is further adapted to determine, based on the nuisance conferee's feedback, whether the at least one nuisance conferee is a disturbing conferee and if the at least one nuisance conferee is not a disturbing conferee than to terminate the mute state or if the at least one nuisance conferee is a disturbing conferee than to continue the mute state.

0069In another embodiment of the first multipoint control unit the control unit is further adapted to inform the disturbing conferee as having been defined as being a disturbing conferee and to recommend redialing. In a further embodiment of the first multipoint control unit the control unit is further adapted to inform the disturbing conferee as having been defined as being a disturbing conferee and to recommend use of a push to talk function.

0070A second multipoint control unit for conducting and controlling a conference between a plurality of conferees, the multipoint control unit comprises a network interface for receiving signals from and providing signals to the plurality of conferees; an analyze and enhance unit coupled to the network interface to analyze and enhance signals received from the plurality of conferees, including a nuisance detector providing an indication if at least one conferee is identified as a nuisance conferee, providing an indication of a feedback indication and providing the enhanced conferee signals; an interactive voice response unit having a control input and a voice output; a switch coupled to the analyze and enhance unit to receive the enhanced conferee signals and the interactive voice response unit to receive the voice output and having a control input and providing conferee signal outputs, the switch responsive to the control input to combine the enhanced conferee signals and the interactive voice response unit output to provide conferee signal outputs; a mixer coupled to the switch to receive the conferee signal outputs and to the network interface to provide output conferee signals and having a control input, the mixer responsive to the control input to mix the conferee signal outputs and interactive voice response output to provide output conferee signals; and a control unit coupled to the analyze and enhance unit to receive nuisance conferee indications and feedback indications, to the interactive noise response unit to provide control, to the switch to provide control and to the mixer to provide control, the control unit adapted to control the interactive voice response unit to provide an output to inform the at least one nuisance conferee and to control the switch and the mixer to place the at least one nuisance conferee in a mute state when the control unit receives a nuisance indication.

0071In an embodiment of the second multipoint control unit the feedback indication indicates the at least one nuisance conferee has returned from hold and wherein the control unit is further adapted to control the switch and the mixer to remove the mute state of the at least one nuisance conferee. Or the feedback indication indicates increasing the nuisance detection level.

0072In a further embodiment of the second multipoint control unit the control unit is further adapted to control the analyze and enhance unit to increase the nuisance detection level of the at least one nuisance conferee; and control the switch and the mixer to remove the mute state of the at least one nuisance conferee.

0073In another embodiment of the second multipoint control unit the control unit is further adapted to determine if the nuisance detection level is above a predetermined level and maintain the mute state of the at least one nuisance conferee if so.

0074In still another embodiment of the second multipoint control unit the control unit is further adapted to control the interactive voice response unit to request the at least one nuisance conferee to terminate and rejoin the conference.

0075In a further embodiment of the second multipoint control unit the feedback indication indicates to cancel nuisance detection and the control unit is further adapted to control the analyze and enhance unit to cancel nuisance detection of the at least one nuisance conferee; and control the switch and the mixer to remove the mute state of the at least one nuisance conferee.

0076In another embodiment of the second multipoint control unit the control unit is further adapted to determine, based on the nuisance conferee's feedback, whether the at least one nuisance conferee is a disturbing conferee and if the at least one nuisance conferee is not a disturbing conferee than to control the switch and the mixer to terminate the mute state or if the at least one nuisance conferee is a disturbing conferee than continue the mute state.

0077In a further embodiment of the second multipoint control unit the control unit is further adapted to control the interactive voice response unit to inform the disturbing conferee as having been defined as being a disturbing conferee and recommend redialing. Or the control unit is further adapted to control the interactive voice response unit to inform the disturbing conferee as having been defined as being a disturbing connection and to recommend use of a push to talk function.