EP2490460B1 - Acoustic feedback suppression for communication terminals - Google Patents

Acoustic feedback suppression for communication terminals Download PDF

Info

Publication number
EP2490460B1
EP2490460B1 EP11155062.0A EP11155062A EP2490460B1 EP 2490460 B1 EP2490460 B1 EP 2490460B1 EP 11155062 A EP11155062 A EP 11155062A EP 2490460 B1 EP2490460 B1 EP 2490460B1
Authority
EP
European Patent Office
Prior art keywords
communication terminal
acoustic
signal
microphone
feedback loop
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
EP11155062.0A
Other languages
German (de)
French (fr)
Other versions
EP2490460A1 (en
Inventor
Alexis Favrot
Christof Faller
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Gigaset Communications GmbH
Original Assignee
Gigaset Communications GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Gigaset Communications GmbH filed Critical Gigaset Communications GmbH
Priority to EP11155062.0A priority Critical patent/EP2490460B1/en
Publication of EP2490460A1 publication Critical patent/EP2490460A1/en
Application granted granted Critical
Publication of EP2490460B1 publication Critical patent/EP2490460B1/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00—Circuits for transducers, loudspeakers or microphones
    • H04R3/02—Circuits for transducers, loudspeakers or microphones for preventing acoustic reaction, i.e. acoustic oscillatory feedback
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2499/00—Aspects covered by H04R or H04S not otherwise provided for in their subgroups
    • H04R2499/10—General applications
    • H04R2499/11—Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's

Definitions

  • the invention relates to a method and a device for suppressing acoustic feedback between communication terminals for mobile voice and / or data communication in a radio-based network.
  • Communication terminals for mobile voice and / or data communication in a radio-based network are nowadays indispensable in private as well as professional life.
  • Acoustic feedbacks are a well-known problem. Acoustic feedback occurs when a loudspeaker emits a signal picked up by a microphone and the loudspeaker is located in the vicinity of the microphone, for example when two mobile phones are in a room and the microphone of the first mobile phone picks up a signal and transmits it the speaker of the second mobile phone is output. The problem arises that the microphone resumes the signal reproduced via the speaker and thus results in a feedback loop between the two mobile phones.
  • US Pat. No. 7,672446 A1 discloses an echo processing device having a receiving device, a connection device to at least one other device, at least one transmission signal containing information transmitted by another communication device and devices for modifying the received signals of the communication device based on various information of the transmission signal and the device hardware.
  • the system includes one or more microphones, A / D, D / A converters, amplifiers and filters that convert an electrical signal to a sound signal via a loudspeaker, and an echo reducer capable of feedback loops to prevent.
  • the object of the invention is to provide a method and a device which avoid one or more disadvantages known from the prior art.
  • a method for suppressing acoustic feedback between communication terminals for mobile voice and / or data communication in a radio-based network comprising at least the method steps: Signaling coupling between a microphone and a loudspeaker, the microphone being part of a first communication terminal and the loudspeaker Part of a second communication terminal is.
  • the presence of an acoustic feedback loop between the first communication terminal and the second communication terminal is determined by means of a feedback loop detector, wherein the acoustic feedback loop is due to feedback of a first acoustic signal in the microphone of the first communication terminal via the speaker of the second communication terminal.
  • the signal intensity between the microphone of the first communication terminal and the loudspeaker of the second communication terminal is reduced by means of a signal amplification control, in the event that the presence of an acoustic feedback loop has been detected.
  • the acoustic echoes between the loudspeaker of the second communication terminal and a second microphone are attenuated by means of an acoustic echo control, wherein the second microphone is part of the second communication terminal, wherein the acoustic echo control received by the second communication terminal, the first acoustic signal of the microphone receives the first communication terminal as the first input signal and receives a second acoustic signal received from the second microphone as a second input signal, the second acoustic signal containing the acoustic echo, wherein the acoustic echo controller outputs an acoustic-echo filtered output signal, wherein the acoustic echo is produced by feedback of the first acoustic signal received by the second communication terminal from the loudspeaker to the
  • the probability of occurrence of the acoustic feedback loop between the first communication terminal and the second communication terminal is determined by the feedback loop detector, wherein the step of determining the likelihood of the occurrence of the acoustic feedback loop between the first communication terminal and the second communication terminal by the feedback loop detector at least comprising: estimating the likelihood of occurrence of the acoustic feedback loop with the addition of a near signal and a far signal, the near signal corresponding to an acoustic echo resulting from feedback of the first acoustic signal received from the second communication terminal from the speaker to the second microphone, and wherein the remote signal of the feedback of the first acoustic signal, in the microphone of the first communication terminal via the speaker of the second Gaynikationsendgerä tes, corresponds.
  • the teaching according to the invention achieves the advantage that at the same time two such systems, for example two mobile telephones or the like, can communicate with one another in the same acoustic space without an acoustic feedback loop building up between these two systems, or such a swinging up of the feedback loop at least reduced or prevented.
  • Communication terminals can be any devices suitable for mobile voice and / or data communication in a radio-based network, for example a mobile telephone.
  • Signaling coupling between a microphone and a loudspeaker means that the signal picked up by a microphone can be sent to a loudspeaker, which can reproduce the signal, that is, output it again.
  • signals which typically picks up a microphone
  • acoustic signals are meant.
  • At least the further method step is additionally provided: attenuation of an acoustic echo between the loudspeaker of the second communication terminal and a second microphone, by means of an acoustic echo control, wherein the second microphone is part of the second communication terminal.
  • the acoustic echo control receives the first acoustic signal of the microphone of the first communication terminal received by the second communication terminal as the first input signal and a second acoustic signal received by the second microphone as the second input signal.
  • the second acoustic signal contains the acoustic echo
  • the acoustic-echo control outputs to the acoustic-echo filtered output signal.
  • the acoustic echo is created by feedback of the first acoustic signal received by the second communication terminal from the loudspeaker to the second microphone.
  • This embodiment ensures that acoustic echoes between the loudspeaker and the microphone of the same communication terminal can be suppressed or at least reduced.
  • Hands-free teleconferencing or videoconferencing systems require an algorithm to suppress unwanted acoustic echo.
  • the acoustic echo results from the coupling between the speaker and the microphone.
  • This embodiment provides such an algorithm.
  • At least the further method step is additionally provided: determining the probability of occurrence of the acoustic feedback loop between the first communication terminal and the second communication terminal, by the feedback loop detector.
  • the advantage is achieved that a prediction can be made about an occurrence probability of an acoustic feedback loop as to whether and when such an acoustic feedback loop will occur in order to be able to counteract this in good time. This increases the reliability of such communication terminals.
  • the probability of occurrence of an acoustic feedback loop can be determined by many types of, for example, predictors.
  • the method step for determining the probability of occurrence of the acoustic feedback loop between the first communication terminal and the second communication terminal, by the feedback loop detector at least
  • the estimation of the probability of the occurrence of the acoustic feedback loop is accompanied by a near signal and a far signal.
  • the near signal corresponds to an acoustic echo which is produced by feedback of the first acoustic signal received by the second communication terminal from the loudspeaker to the second microphone.
  • the remote signal corresponds to the feedback of the first acoustic signal in the microphone of the first communication terminal via the loudspeaker of the second communication terminal.
  • the estimation of the likelihood of the occurrence of the acoustic feedback loop also occurs with the additional addition of coherence between the near signal and the far signal.
  • This embodiment achieves the advantage that the probability of occurrence of an acoustic feedback loop can be predicted in a particularly precise manner, in particular by including the coherence between the near signal and the remote signal.
  • feedback detection rules can be derived to reduce the full-band signal gain of the loudspeaker accordingly.
  • K corresponds to the number of the time frame and ⁇ att corresponds to a time constant.
  • g L denotes the maximum allowable signal gain reduction.
  • the feedback loop detector and the signal amplification control are part of the second communication terminal. It is further provided, at least, for the signal amplification controller to carry out the signal amplification of the first acoustic signal received by the second communication terminal on the loudspeaker of the second communication terminal.
  • This embodiment achieves the advantage that only one communication terminal according to the invention is required during the communication in order to inhibit the emergence of a feedback loop between this communication device and another communicating therewith, ie to suppress or at least mitigate it.
  • the feedback loop detector and the signal amplification control are part of this communication terminal, other solutions are conceivable, for example a feedback loop detector and / or a signal amplification control which are arranged in the further communication device or distributed over both communication devices ,
  • the first communication terminal and the second communication terminal are connected to one another via a communication and / or data network which supports the DECT standard.
  • This embodiment achieves the advantage that an already very well available and established standard for mobile communication can be used for the communication between the communication terminals.
  • Independent claim 7 provides a communication terminal for mobile voice and / or data communication in a radio-based network, wherein the communication terminal has at least one loudspeaker, a microphone and a connection to the radio-based network.
  • the communication terminal is set up to receive a first acoustic signal via the connection to the radio-based network and the microphone is set up to receive a second acoustic signal.
  • the communication terminal further comprises at least one first device, configured to determine the presence of an acoustic feedback loop between the communication terminal and a second communication terminal.
  • the acoustic feedback loop is due to feedback of a first acoustic signal in a second microphone of a second communication terminal via the loudspeaker of the communication terminal.
  • the communication terminal further comprises a second device, configured to reduce the signal intensity between the second microphone of the second communication terminal and the loudspeaker of the communication terminal, in the event that the presence of an acoustic feedback loop has been detected.
  • an inventive communication terminal is provided for the method described above.
  • the communication terminal further comprises at least a third device, which is adapted to attenuate an acoustic echo between the loudspeaker of the communication terminal and the microphone of the communication device.
  • the acoustic echo is created by feedback of the first acoustic signal received by the communication terminal from the loudspeaker to the second microphone.
  • This embodiment ensures that acoustic echoes between the loudspeaker and the microphone of the same communication terminal can be suppressed or at least reduced.
  • the communication terminal is also at least configured to communicate in a communication and / or data network which supports the DECT standard.
  • This embodiment achieves the advantage that an already very well available and established standard for mobile communication can be used for the communication between the communication terminals.
  • the inventive method and the device for suppressing acoustic feedback between communication terminals for mobile voice and / or data communication in a radio-based network are described below in one embodiment and shown in the drawing.
  • FIG. 1 shows an embodiment according to a preferred embodiment of the invention Fig. 1
  • the two communication terminals 100, 200 are located in the same room and the distance between the two communication terminals 100, 200 is such that a feedback loop (communication path 110, 330, 310, 220, 340) 320 can arise. This may be due to a direct sound transmission between the speaker 220 of the second communication terminal 200 and the microphone 110 of the first communication terminal 110 or by a reflected sound transmission between the same.
  • a feedback loop communication path 110, 330, 310, 220, 340
  • a user 900 speaks into the microphone 110 of the first communication terminal 100, while both communication terminals 100, 200 communicate with each other via a radio-based network 230.
  • the user 900 language is received as an acoustic signal 330 from the microphone 110 of the first communication terminal 100 and transmitted via the radio-based network 230 to the second communication terminal 200.
  • the received signal is forwarded as an acoustic signal 330 to the loudspeaker 220 of the second communication terminal 200.
  • the acoustic echo controller 600 Prior to this, however, it is applied to both the acoustic echo controller 600 as the first input signal 610 and the feedback loop detector 400.
  • the feedback loop detector 400 of the second communication terminal 200 includes both the device for detecting the presence of an acoustic signal Feedback loop 320 integrated, as well as the device for reducing the signal intensity at the speaker 220 of the second communication terminal 200 in the event that the presence of an acoustic feedback loop 320 has been determined.
  • the optionally acoustically reduced acoustic signal 330 is then output at the loudspeaker 220 of the second communication terminal 200.
  • an acoustic echo 350 may arise between this loudspeaker 220 and the microphone 210 of the second communication terminal 200.
  • the acoustic signal received by this microphone 210 may therefore include the acoustic echo 350 and is supplied to the acoustic echo controller 600 as a second input signal 610 to filter the acoustic signal picked up by the microphone 210 and to be corrected for the acoustic echo 350 Signal 640 via the radio-based network 230 to the first communication terminal 100 to send.
  • the acoustic signal output by the speaker 220 of the second communication terminal 200 may, for example via reflection in the space 340, return to the microphone and thereby provide a feedback loop 320 (therefore described as a path) between the two communication terminals 100, 200.
  • the acoustic signal has been signal-reduced in the second communication terminal 200 upon detection of a feedback loop 320 before it is output by the loudspeaker 220 of the second communication terminal 200, further oscillation of a feedback loop 320 is substantially prevented.

Abstract

The method involves providing a signal-technical coupling (310) between a microphone (110) of a communication terminal (100) and a loudspeaker (220) of another communication terminal (200). An existence of an acoustic feedback loop between the terminals is determined by a feedback loop-detector (400). The feedback loop is conditioned by feedback (340) of an acoustic signal (330) in the microphone over the loudspeaker. A signal intensity between the microphone and the loudspeaker is reduced by a signal gain control when the existence of the feedback loop is determined. An independent claim is also included for a communication terminal.

Description

Die Erfindung betrifft ein Verfahren und eine Vorrichtung zur Unterdrückung von akustischen Feedbacks zwischen Kommunikationsendgeräten zur mobilen Sprach- und/oder Datenkommunikation in einem funkbasierten Netzwerk.The invention relates to a method and a device for suppressing acoustic feedback between communication terminals for mobile voice and / or data communication in a radio-based network.

Kommunikationsendgeräte zur mobilen Sprach- und/oder Datenkommunikation in einem funkbasierten Netzwerk sind heutzutage aus dem Privat- wie auch dem Berufsleben nicht mehr wegzudenken.Communication terminals for mobile voice and / or data communication in a radio-based network are nowadays indispensable in private as well as professional life.

Akustische Feedbacks sind dabei ein weit bekanntes Problem. Akustische Feedbacks treten auf, wenn ein Lautsprecher ein Signal ausgibt, welches von einem Mikrofon aufgenommen wurde und der Lautsprecher in räumlicher Nähe des Mikrofons angeordnet ist, beispielsweise wenn sich zwei Mobiltelefone in einem Raum befinden und das Mikrofon des ersten Mobiltelefons ein Signal aufnimmt und dieses über den Lautsprecher des zweiten Mobiltelefons ausgegeben wird. Dabei tritt das Problem auf, dass das Mikrofon das über den Lautsprecher reproduzierte Signal erneut aufnimmt und sich somit eine Feedbackschleife zwischen den beiden Mobiltelefonen ergibt.Acoustic feedbacks are a well-known problem. Acoustic feedback occurs when a loudspeaker emits a signal picked up by a microphone and the loudspeaker is located in the vicinity of the microphone, for example when two mobile phones are in a room and the microphone of the first mobile phone picks up a signal and transmits it the speaker of the second mobile phone is output. The problem arises that the microphone resumes the signal reproduced via the speaker and thus results in a feedback loop between the two mobile phones.

Bei geringer Lautstärke und genügend großem Abstand zwischen Mikrofon und Lautsprecher tritt die Feedback-Problematik hingegen nicht auf. Wird die Lautstärke des Lautsprechers jedoch erhöht, kann es zu Störgeräuschen kommen und im schlimmsten Fall zu Systeminstabilität führen.At low volume and enough distance between the microphone and the speaker, the feedback problem does not occur. Increasing the volume of the speaker, however, may cause noise and, in the worst case scenario, cause system instability.

Eine Möglichkeit zur Unterdrückung unerwünschter Echos zwischen zwei Kommunikationsvorrichtungen beschreibt zum Beispiel die US 7,672446 A1 . Diese offenbart eine Echo-Verarbeitungsvorrichtung mit einer Empfangsvorrichtung, einer Verbindungsvorrichtung zu mindestens einer anderen Vorrichtung, wenigstens einem Übertragungssignal enthaltend Informationen, welche von einer andere Kommunikationseinrichtung übermittelt werden und Vorrichtungen um die aufgenommenen Signale der Kommunikationseinrichrung anhand diverser Informationen des Übertragungssignals und der Vorrichtungshardware zu modifizieren.One way of suppressing unwanted echoes between two communication devices, for example, describes US Pat. No. 7,672446 A1 , This discloses an echo processing device having a receiving device, a connection device to at least one other device, at least one transmission signal containing information transmitted by another communication device and devices for modifying the received signals of the communication device based on various information of the transmission signal and the device hardware.

Eine weitere Möglichkeit zur Verhinderung von Echos und Umweltgeräuschen in Umgebungen mit veränderlichem Geräuschpegel, wie zum Beispiel einem Fahrzeug, bietet die EP 1429315 A1 . Das System beinhaltet ein oder mehrere Mikrophone, A/D-, D/A-Wandler, Verstärker und Filter, welche ein elektrisches Signal mittels eines Lautsprechers in ein akustisches Signal umwandeln, sowie eine Echo-Reduziervorrichtung, welche in der Lage ist Feedback-Schleifen zu verhindern.Another way to prevent echoes and environmental noise in variable noise environments, such as a vehicle, is the EP 1429315 A1 , The system includes one or more microphones, A / D, D / A converters, amplifiers and filters that convert an electrical signal to a sound signal via a loudspeaker, and an echo reducer capable of feedback loops to prevent.

Aufgabe der Erfindung ist es ein Verfahren und eine Vorrichtung zur Verfügung zu stellen, die eine oder mehrere aus dem Stand der Technik bekannten Nachteile vermeiden.The object of the invention is to provide a method and a device which avoid one or more disadvantages known from the prior art.

Diese Aufgabe wird gelöst durch den Gegenstand des Anspruchs 1.This object is achieved by the subject matter of claim 1.

Vorgestellt wird ein Verfähren zur Unterdrückung von akustischen Feedbacks zwischen Kommunikationsendgeräten zur mobilen Sprach- und/oder Datenkommunikation in einem funkbasierten Netzwerk, umfassend zumindest die Verfahrensschritte: Signaltechnisches koppeln zwischen einem Mikrofon und einem Lautsprecher, wobei das Mikrofon Bestandteil eines ersten Kommunikationsendgerätes ist und wobei der Lautsprecher Bestandteil eines zweiten Kommunikationsendgerätes ist. Das Vorliegen einer akustischen Feedbackschleife zwischen dem ersten Kommunikationsendgerät und dem zweiten Kommunikationsendgerät, wird mittels eines Feedbackschleifen-Detektors ermittelt, wobei die akustische Feedbackschleife durch Rückkopplung eines ersten akustischen Signals in dem Mikrofon des ersten Kommunikationsendgerätes über den Lautsprecher des zweiten Kommunikationsendgerätes bedingt ist. Die Signalintensität zwischen dem Mikrofon des ersten Kommunikationsendgerätes und des Lautsprechers des zweiten Kormunikationsendgerätes wird mittels einer Signalverstärkungssteuerung reduziert, für den Fall, dass das Vorliegen einer akustischen Feedbackschleife ermittelt wurde. Die akustischen Echos zwischen dem Lautsprecher des zweiten Kommunikationsendgerätes und einem zweiten Mikrofon werden mittels einer akustischen Echo-Steuerung gedämpft, wobei das zweite Mikrofon Bestandteil des zweiten Kommunikationsendgerätes ist, wobei die akustische-Echo-Steuerung das vom zweiten Kommunikationsendgerät empfangene, erste akustische Signal des Mikrofons des ersten Kommunikationsendgerätes als erstes Eingabesignal erhält und ein vom zweiten Mikrofon empfangenes, zweites akustisches Signal als zweites Eingabesignal erhält, wobei das zweite akustische Signal das akustische Echo enthält, wobei die akustische-Echo-Steuerung ein um das akustische-Echo gefiltertes Ausgabesignal ausgibt, wobei das akustische Echo durch Rückkopplung des, vom zweiten Kommunikationsendgerät empfangenen, ersten akustischen Signals vom Lautsprecher zum zweiten Mikrofon entsteht. Die Wahrscheinlichkeit des Auftretens der akustischen FeedbackSchleife zwischen dem ersten Kommunikationsendgerät und dem zweiten Kommunikationsendgerät wird durch den Feedbackschleifen-Detektor bestimmt, wobei der Verfahrensschritt zur Bestimmung der Wahrscheinlichkeit des Auftretens der akustischen Feedback-Schleife zwischen dem ersten Kommunikationsendgerät und dem zweiten Kommunikationsendgerät durch den Feedbackschleifen-Detektor zumindest umfasst: Abschätzen der Wahrscheinlichkeit des Auftretens der akustischen Feedback-Schleife unter Hinzunahme eines Nahsignals und eines Fernsignals, wobei das Nahsignal einem akustischen Echo entspricht, welches durch Rückkopplung des, vom zweiten Kommunikationsendgerät empfangenen, ersten akustischen Signals vom Lautsprecher zum zweiten Mikrofon entsteht, und wobei das Fernsignal der Rückkopplung des ersten akustischen Signals, in dem Mikrofon des ersten Kommunikationsendgerätes über den Lautsprecher des zweiten Kommunikationsendgerätes, entspricht.Disclosed is a method for suppressing acoustic feedback between communication terminals for mobile voice and / or data communication in a radio-based network comprising at least the method steps: Signaling coupling between a microphone and a loudspeaker, the microphone being part of a first communication terminal and the loudspeaker Part of a second communication terminal is. The presence of an acoustic feedback loop between the first communication terminal and the second communication terminal is determined by means of a feedback loop detector, wherein the acoustic feedback loop is due to feedback of a first acoustic signal in the microphone of the first communication terminal via the speaker of the second communication terminal. The signal intensity between the microphone of the first communication terminal and the loudspeaker of the second communication terminal is reduced by means of a signal amplification control, in the event that the presence of an acoustic feedback loop has been detected. The acoustic echoes between the loudspeaker of the second communication terminal and a second microphone are attenuated by means of an acoustic echo control, wherein the second microphone is part of the second communication terminal, wherein the acoustic echo control received by the second communication terminal, the first acoustic signal of the microphone receives the first communication terminal as the first input signal and receives a second acoustic signal received from the second microphone as a second input signal, the second acoustic signal containing the acoustic echo, wherein the acoustic echo controller outputs an acoustic-echo filtered output signal, wherein the acoustic echo is produced by feedback of the first acoustic signal received by the second communication terminal from the loudspeaker to the second microphone. The probability of occurrence of the acoustic feedback loop between the first communication terminal and the second communication terminal is determined by the feedback loop detector, wherein the step of determining the likelihood of the occurrence of the acoustic feedback loop between the first communication terminal and the second communication terminal by the feedback loop detector at least comprising: estimating the likelihood of occurrence of the acoustic feedback loop with the addition of a near signal and a far signal, the near signal corresponding to an acoustic echo resulting from feedback of the first acoustic signal received from the second communication terminal from the speaker to the second microphone, and wherein the remote signal of the feedback of the first acoustic signal, in the microphone of the first communication terminal via the speaker of the second Kommunikationsendgerä tes, corresponds.

Dies unter unter zusätzlicher Hinzunahme der Kohärenz zwischen dem Nahsignal und dem Fernsignal.This with the additional addition of coherence between the near signal and the far signal.

Kommunizieren zur selben Zeit zwei solcher Systeme im selben akustischen Raum, wird eine akustische Feedbackschleife zwischen beiden Systemen erzeugt.At the same time, when two such systems are communicating in the same acoustic space, an acoustic feedback loop is generated between the two systems.

Durch die erfindungsgemäße Lehre wird der Vorteil erreicht, dass zur selben Zeit zwei solcher Systeme, beispielsweise zwei Mobiltelefone oder ähnliches, im selben akustischen Raum miteinander kommunizieren können, ohne dass sich zwischen diesen beiden Systemen eine akustische Feedbackschleife aufbaut, oder dass solch ein aufschwingen der Feedbackschleife zumindest vermindert oder verhindert werden kann.The teaching according to the invention achieves the advantage that at the same time two such systems, for example two mobile telephones or the like, can communicate with one another in the same acoustic space without an acoustic feedback loop building up between these two systems, or such a swinging up of the feedback loop at least reduced or prevented.

Kommunikationsendgeräte können dabei jegliche, zur mobilen Sprach- und/oder Datenkommunikation in einem funkbasierten Netzwerk, geeigneten Vorrichtungen sein, beispielsweise ein Mobiltelefon.Communication terminals can be any devices suitable for mobile voice and / or data communication in a radio-based network, for example a mobile telephone.

Signaltechnisches koppeln zwischen einem Mikrofon und einem Lautsprecher meint dabei, dass das von einem Mikrofon aufgenommene Signal zu einem Lautsprecher gesandt werden kann, der das Signal reproduzieren, also wieder ausgeben kann.Signaling coupling between a microphone and a loudspeaker means that the signal picked up by a microphone can be sent to a loudspeaker, which can reproduce the signal, that is, output it again.

Als Signale, die ein Mikrofon dabei typischerweise aufnimmt, sind akustische Signale gemeint.As signals, which typically picks up a microphone, acoustic signals are meant.

Bevorzugte Weiterbildungen der Erfindung sind in den Unteransprüchen beschrieben.Preferred developments of the invention are described in the subclaims.

In einer besonders vorteilhaften Ausführungsform der Erfindung ist darüber hinaus zumindest der weitere Verfahrensschritt vorgesehen: Dämpfen eines akustischen Echos zwischen dem Lautsprecher des zweiten Kommunikationsendgerätes und einem zweiten Mikrofon, mittels einer akustischen-Echo-Steuerung, wobei das zweite Mikrofon Bestandteil des zweiten Kommunikationsendgerätes ist. Die akustische-Echo-Steuerung erhält dabei das, vom zweiten Kommunikationsendgerät empfangene, erste akustische Signal des Mikrofons des ersten Kommunikationsendgerätes als erstes Eingabesignal und ein vom zweiten Mikrofon empfangenes, zweites akustisches Signal als zweites Eingabesignal. Dabei enthält das zweite akustische Signal das akustische Echo, und die akustische-Echo-Steuerung gibt ein, um das akustische-Echo gefiltertes Ausgabesignal aus. Dabei entsteht das akustische Echo durch Rückkopplung des, vom zweiten Kommunikationsendgerät empfangenen, ersten akustischen Signals vom Lautsprecher zum zweiten Mikrofon.In a particularly advantageous embodiment of the invention, at least the further method step is additionally provided: attenuation of an acoustic echo between the loudspeaker of the second communication terminal and a second microphone, by means of an acoustic echo control, wherein the second microphone is part of the second communication terminal. In this case, the acoustic echo control receives the first acoustic signal of the microphone of the first communication terminal received by the second communication terminal as the first input signal and a second acoustic signal received by the second microphone as the second input signal. In this case, the second acoustic signal contains the acoustic echo, and the acoustic-echo control outputs to the acoustic-echo filtered output signal. In this case, the acoustic echo is created by feedback of the first acoustic signal received by the second communication terminal from the loudspeaker to the second microphone.

Durch diese Ausführungsform wird erreicht, dass akustische Echos zwischen dem Lautsprecher und dem Mikrofon desselben Kommunikationsendgerätes unterdrückt oder zumindest reduziert werden können.This embodiment ensures that acoustic echoes between the loudspeaker and the microphone of the same communication terminal can be suppressed or at least reduced.

Freihändig zu bedienende Tele- oder Videokonferenzsysteme benötigen einen Algorithmus um unerwünschtes akustisches Echo zu unterdrücken. Das akustische Echo resultiert dabei aus der Kopplung zwischen dem Lautsprecher und dem Mikrofon.Hands-free teleconferencing or videoconferencing systems require an algorithm to suppress unwanted acoustic echo. The acoustic echo results from the coupling between the speaker and the microphone.

Durch diese Ausführungsform wird solch ein Algorithmus zur Verfügung gestellt.This embodiment provides such an algorithm.

In einer weiteren besonders vorteilhaften Ausführungsform der Erfindung ist darüber hinaus zumindest der weitere Verfahrensschritt vorgesehen: Bestimmen der Wahrscheinlichkeit des Auftretens der akustischen Feedback-Schleife zwischen dem ersten Kommunikationsendgerät und dem zweiten Kommunikationsendgerät, durch den Feedbackschleifen-Detektor.In a further particularly advantageous embodiment of the invention, at least the further method step is additionally provided: determining the probability of occurrence of the acoustic feedback loop between the first communication terminal and the second communication terminal, by the feedback loop detector.

Durch diese Ausführungsform wird der Vorteil erreicht, dass über eine Auftrittswahrscheinlichkeit einer akustischen Feedbackschleife eine Vorhersage getroffen werden kann, ob und wann eine solche akustische Feedbackschleife auftreten wird, um dieser rechtzeitig entgegenwirken zu können. Dies erhöht die Zuverlässigkeit solcher Kommunikationsendgeräte.By means of this embodiment, the advantage is achieved that a prediction can be made about an occurrence probability of an acoustic feedback loop as to whether and when such an acoustic feedback loop will occur in order to be able to counteract this in good time. This increases the reliability of such communication terminals.

Die Auftrittswahrscheinlichkeit einer akustischen Feedbackschleife kann durch vielerlei Arten von beispielsweise Prädiktoren ermittelt werden.The probability of occurrence of an acoustic feedback loop can be determined by many types of, for example, predictors.

In einer weiteren besonders vorteilhaften Ausführungsform der Erfindung ist darüber hinaus zumindest vorgesehen, dass der Verfahrensschritt zur Bestimmung der Wahrscheinlichkeit des Auftretens der akustischen Feedback-Schleife zwischen dem ersten Kommunikationsendgerät und dem zweiten Kommunikationsendgerät, durch den Feedbackschleifen-Detektor zumindest umfasst: Das Abschätzen der Wahrscheinlichkeit des Auftretens der akustischen Feedback-Schleife erfolgt unter hinzunahme eines Nahsignals und eines Fernsignals. Dabei entspricht das Nahsignal einem akustischen Echo, welches durch Rückkopplung des, vom zweiten Kommunikationsendgerät empfangenen, ersten akustischen Signals vom Lautsprecher zum zweiten Mikrofon entsteht. Darüber hinaus entspricht dabei das Fernsignal der Rückkopplung des ersten akustischen Signals in dem Mikrofon des ersten Kommunikationsendgerätes über den Lautsprecher des zweiten Kommunikationsendgerätes. Das Abschätzen der Wahrscheinlichkeit des Auftretens der akustischen Feedbackschleife erfolgt darüber hinaus unter zusätzlicher Hinzunahme der Kohärenz zwischen dem Nahsignal und dem Fernsignal.In a further particularly advantageous embodiment of the invention, it is additionally provided that the method step for determining the probability of occurrence of the acoustic feedback loop between the first communication terminal and the second communication terminal, by the feedback loop detector at least The estimation of the probability of the occurrence of the acoustic feedback loop is accompanied by a near signal and a far signal. In this case, the near signal corresponds to an acoustic echo which is produced by feedback of the first acoustic signal received by the second communication terminal from the loudspeaker to the second microphone. Moreover, the remote signal corresponds to the feedback of the first acoustic signal in the microphone of the first communication terminal via the loudspeaker of the second communication terminal. The estimation of the likelihood of the occurrence of the acoustic feedback loop also occurs with the additional addition of coherence between the near signal and the far signal.

Durch diese Ausführungsform wird der Vorteil erreicht, dass die Auftrittswahrscheinlichkeit einer akustischen Feedbackschleife besonders präzise vorhergesagt werden kann, indem insbesondere die Kohärenz zwischen dem Nahsignal und dem Fernsignal mit einbezogen wird.This embodiment achieves the advantage that the probability of occurrence of an acoustic feedback loop can be predicted in a particularly precise manner, in particular by including the coherence between the near signal and the remote signal.

Unter Berücksichtigung des Mikrofon- und Lautsprechersignals des zweiten Kommunikationsendgerätes können Feedback-Erkennungsregeln abgeleitet werden, um die Vollband-Signalverstärkung des Lautsprechers entsprechend zu reduzieren.Taking into account the microphone and loudspeaker signal of the second communication terminal, feedback detection rules can be derived to reduce the full-band signal gain of the loudspeaker accordingly.

Sobald ein Feedback erkannt wird, kann die Signalverstärkung gfbc nach folgendem Muster angepasst werden: g fbc k = _α att * g L + 1 - _α att * g fbc ⁢ k - 1

Figure imgb0001
Once a feedback is detected, the signal gain g fbc can be adjusted according to the following pattern: G fbc k = _α att * G L + 1 - _α att * G fbc ⁢ k - 1
Figure imgb0001

Dabei entspricht k der Nummer des Zeitrahmens und αatt entspricht einer Zeitkonstanten. gL bezeichnet die maximal erlaubte Reduzierung der Signalverstärkung.K corresponds to the number of the time frame and α att corresponds to a time constant. g L denotes the maximum allowable signal gain reduction.

Wird kein Feedback mehr erkannt, kann die Signalverstärkung wieder in den unreduzierten Zustand zurückgeführt werden, nach: g fbc k = _α rel + 1 - _α rel * g fbc ⁢ k - 1 , mit α rel als Relaxationszeitkonstante .

Figure imgb0002
If no feedback is detected, the signal gain can be returned to the unreduced state after: G fbc k = _α rel + 1 - _α rel * G fbc ⁢ k - 1 . With α rel as relaxation time constant ,
Figure imgb0002

In einer weiteren besonders vorteilhaften Ausführungsform der Erfindung ist darüber hinaus zumindest vorgesehen, dass der Feedbackschleifen-Detektor und die Signalverstärkungssteuerung Bestandteil des zweiten Kommunikationsendgerätes sind. Weiter ist zumindest vorgesehen, dass die Signalverstärkungssteuerung die Signalverstärkung des, vom zweiten Kommunikationsendgerät empfangenen, ersten akustischen Signals am Lautsprecher des zweiten Kommunikationsendgerätes vornimmt.In a further particularly advantageous embodiment of the invention, it is additionally provided, at least, for the feedback loop detector and the signal amplification control to be part of the second communication terminal. It is further provided, at least, for the signal amplification controller to carry out the signal amplification of the first acoustic signal received by the second communication terminal on the loudspeaker of the second communication terminal.

Durch diese Ausführungsform wird der Vorteil erreicht, dass lediglich ein erfindungsgemäßes Kommunikationsendgerät während der Kommunikation benötigt wird, um das Entstehen einer Feedbackschleife zwischen diesem Kommunikationsgerät und einem weiteren sich mit diesem in Kommunikation befindlichen zu hemmen, also zu unterdrücken oder zumindest abzumildern.This embodiment achieves the advantage that only one communication terminal according to the invention is required during the communication in order to inhibit the emergence of a feedback loop between this communication device and another communicating therewith, ie to suppress or at least mitigate it.

Es ist jedoch nicht unbedingt zwingend erforderlich, dass der Feedbackschleifen-Detektor und die Signalverstärkungssteuerung Bestandteil dieses Kommunikationsendgerätes sind, andere Lösungen sind denkbar, beispielsweise ein Feedbackschleifen-Detektor und/oder eine Signalverstärkungssteuerung die in dem weiteren Kommunikationsgerät angeordnet sind oder über beide Kommunikationsgeräte verteilt angeordnet sind.However, it is not absolutely necessary that the feedback loop detector and the signal amplification control are part of this communication terminal, other solutions are conceivable, for example a feedback loop detector and / or a signal amplification control which are arranged in the further communication device or distributed over both communication devices ,

In einer weiteren besonders vorteilhaften Ausführungsform der Erfindung ist darüber hinaus zumindest vorgesehen, dass das erste Kommunikationsendgerät und das zweite Kommunikationsendgerät über ein Kommunikations- und/oder Datennetzwerk miteinander verbunden sind, welches den DECT-Standard unterstützt.In a further particularly advantageous embodiment of the invention, moreover, at least provision is made for the first communication terminal and the second communication terminal to be connected to one another via a communication and / or data network which supports the DECT standard.

Durch diese Ausführungsform wird der Vorteil erreicht, dass zur Kommunikation zwischen den Kommunikationsendgeräten ein bereits sehr gut verfügbarer und etablierter Standard zur mobilen Kommunikation verwendet werden kann.This embodiment achieves the advantage that an already very well available and established standard for mobile communication can be used for the communication between the communication terminals.

Die Verwendung in diesem Standard ist jedoch nicht zwingend und auch nicht abschließend, vielmehr sind weitere aktuelle und zukünftige mobile Kommunikationsstandards verwendbar, beispielsweise GSM, EDGE, HSDPA, UMTS, Bluetooth, und viele weitere.However, the use in this standard is not mandatory and not exhaustive, but more current and future mobile communication standards are usable, such as GSM, EDGE, HSDPA, UMTS, Bluetooth, and many more.

Der unabhängige Anspruch 7 stellt ein Kommunikationsendgerät zur mobilen Sprach- und/oder Datenkommunikation in einem funkbasierten Netzwerk zur Verfügung, wobei das Kommunikationsendgerät zumindest einen Lautsprecher, ein Mikrofon und eine Anbindung zum funkbasierten Netzwerk aufweist. Dabei ist das Kommunikationsendgerät dazu eingerichtet, über die Anbindung zum funkbasierten Netzwerk ein erstes akustisches Signal zu empfangen und das Mikrofon ist dazu eingerichtet, ein zweites akustisches Signal zu empfangen. Das Kommunikationsendgerät umfasst darüber hinaus zumindest eine erste Vorrichtung, dazu eingerichtet, das Vorliegen einer akustischen Feedbackschleife zwischen dem Kommunikationsendgerät und einem zweiten Kommunikationsendgerät zu ermitteln. Dabei ist die akustische Feedbackschleife durch Rückkopplung eines ersten akustischen Signals in einem zweiten Mikrofon eines zweiten Kommunikationsendgerätes über den Lautsprecher des Kommunikationsendgerätes bedingt. Das Kommunikationsendgerät umfasst desweiteren darüber hinaus eine zweite Vorrichtung, dazu eingerichtet, die Signalintensität zwischen dem zweiten Mikrofon des zweiten Kommunikationsendgerätes und des Lautsprechers des Kommunikationsendgerätes zu reduzieren, für den Fall, dass das Vorliegen einer akustischen Feedbackschleife ermittelt wurde.Independent claim 7 provides a communication terminal for mobile voice and / or data communication in a radio-based network, wherein the communication terminal has at least one loudspeaker, a microphone and a connection to the radio-based network. In this case, the communication terminal is set up to receive a first acoustic signal via the connection to the radio-based network and the microphone is set up to receive a second acoustic signal. The communication terminal further comprises at least one first device, configured to determine the presence of an acoustic feedback loop between the communication terminal and a second communication terminal. In this case, the acoustic feedback loop is due to feedback of a first acoustic signal in a second microphone of a second communication terminal via the loudspeaker of the communication terminal. Furthermore, the communication terminal further comprises a second device, configured to reduce the signal intensity between the second microphone of the second communication terminal and the loudspeaker of the communication terminal, in the event that the presence of an acoustic feedback loop has been detected.

Damit wird für das oben beschriebene Verfahren ein erfindungsgemäßes Kommunikationsendgerät zur Verfügung gestellt.Thus, an inventive communication terminal is provided for the method described above.

In einer besonders vorteilhaften Ausführungsform der Erfindung ist darüber hinaus vorgesehen, dass das Kommunikationsendgerät darüber hinaus zumindest eine dritte Vorrichtung umfasst, die dazu eingerichtet, ein akustisches Echo zwischen dem Lautsprecher des Kommunikationsendgerätes und dem Mikrofon des Kommunikationsgerätes, zu dämpfen. Dabei entsteht das akustische Echo durch Rückkopplung des, vom Kommunikationsendgerät empfangenen, ersten akustischen Signals vom Lautsprecher zum zweiten Mikrofon.In a particularly advantageous embodiment of the invention, moreover, it is provided that the communication terminal further comprises at least a third device, which is adapted to attenuate an acoustic echo between the loudspeaker of the communication terminal and the microphone of the communication device. In this case, the acoustic echo is created by feedback of the first acoustic signal received by the communication terminal from the loudspeaker to the second microphone.

Durch diese Ausführungsform wird erreicht, dass akustische Echos zwischen dem Lautsprecher und dem Mikrofon desselben Kommunikationsendgerätes unterdrückt oder zumindest reduziert werden können.This embodiment ensures that acoustic echoes between the loudspeaker and the microphone of the same communication terminal can be suppressed or at least reduced.

In einer weiteren besonders vorteilhaften Ausführungsform der Erfindung ist darüber hinaus vorgesehen, dass das Kommunikationsendgerät darüber hinaus zumindest dazu eingerichtet ist, in einem Kommunikations- und/oder Datennetzwerk zu kommunizieren, welches den DECT-Standard unterstützt.In a further particularly advantageous embodiment of the invention, moreover, it is provided that the communication terminal is also at least configured to communicate in a communication and / or data network which supports the DECT standard.

Durch diese Ausführungsform wird der Vorteil erreicht, dass zur Kommunikation zwischen den Kommunikationsendgeräten ein bereits sehr gut verfügbarer und etablierter Standard zur mobilen Kommunikation verwendet werden kann.This embodiment achieves the advantage that an already very well available and established standard for mobile communication can be used for the communication between the communication terminals.

Diese Beispiele sind nicht abschließend zu sehen.These examples are not conclusive.

Das erfindungsgemäße Verfahren und die Vorrichtung zur Unterdrückung von akustischen Feedbacks zwischen Kommunikationsendgeräten zur mobilen Sprach- und/oder Datenkommunikation in einem funkbasierten Netzwerk sind nachfolgend in einem Ausführungsbeispiel beschrieben und zeichnerisch dargestellt.The inventive method and the device for suppressing acoustic feedback between communication terminals for mobile voice and / or data communication in a radio-based network are described below in one embodiment and shown in the drawing.

Die Zeichnung zeigt eine Ausführungsform gemäß einer bevorzugten Ausgestaltung der Erfindung mit Fig. 1 The drawing shows an embodiment according to a preferred embodiment of the invention Fig. 1

In der Zeichnung zeigen:

  • Fig. 1 skizzenhaft dargestellt ist ein Szenario einer möglichen erfindungsgemäßen Verwendung zweier benachbarter Kommunikationsendgeräte.
  • Fig. 1 zeigt ein Szenario einer möglichen erfindungsgemäßen Verwendung zweier benachbarter Kommunikationsendgeräte 100, 200. Das erste Kommunikationsendgerät 100 umfasst dabei zumindest ein Mikrofon 110, einen Lautsprecher 120, eine akustisches-Echo-Steuerung 600' und einen Feedbackschleifen-Detektor 400'. Das zweite Kommunikationsendgerät 200 umfasst dabei ebenfalls zumindest ein Mikrofon 210, einen Lautsprecher 220, eine akustisches-Echo-Steuerung 600 und einen Feedbackschleifen-Detektor 400. Das erste Kommunikationsendgerät 100 kann auch ein anderes Kommunikationsendgerät sein, das geeignet ist, in einem funkbasierten Netzwerk zur mobilen Sprach- und/oder Datenkommunikation zu kommunizieren.
In the drawing show:
  • Fig. 1 sketched out is a scenario of a possible inventive use of two adjacent communication terminals.
  • Fig. 1 shows a scenario of a possible inventive use of two adjacent communication terminals 100, 200. The first communication terminal 100 includes at least one microphone 110, a speaker 120, an acoustic echo controller 600 'and a feedback loop detector 400'. The second communication terminal 200 likewise comprises at least one microphone 210, a loudspeaker 220, an acoustic-echo controller 600 and a feedback loop detector 400. The first communication terminal 100 can also be another communication terminal that is suitable for use in a radio-based network mobile voice and / or data communication.

Die beiden Kommunikationsendgeräte 100, 200 befindet sich im selben Raum und der Abstand zwischen beiden Kommunikationsendgeräten 100, 200 ist derart, dass eine Feedbackschleife (Kommunikationsweg 110, 330,310, 220, 340) 320 entstehen kann. Diese kann durch eine direkte Schallübertragung zwischen dem Lautsprecher 220 des zweiten Kommunikationsendgerätes 200 und dem Mikrofon 110 des ersten Kommunikationsendgerätes 110 oder durch eine reflektierte Schallübertragung zwischen selbigen begründet sein.The two communication terminals 100, 200 are located in the same room and the distance between the two communication terminals 100, 200 is such that a feedback loop (communication path 110, 330, 310, 220, 340) 320 can arise. This may be due to a direct sound transmission between the speaker 220 of the second communication terminal 200 and the microphone 110 of the first communication terminal 110 or by a reflected sound transmission between the same.

Ein Benutzer 900 spricht in das Mikrofon 110 des ersten Kommunikationsendgerätes 100, während beide Kommunikationsendgeräte 100, 200 über ein funkbasiertes Netzwerk 230 miteinander kommunizieren.A user 900 speaks into the microphone 110 of the first communication terminal 100, while both communication terminals 100, 200 communicate with each other via a radio-based network 230.

Die Sprache Benutzers 900 wird als akustisches Signal 330 von dem Mikrofon 110 des ersten Kommunikationsendgerätes 100 aufgenommen und über das funkbasierte Netzwerk 230 zu dem zweiten Kommunikationsendgerät 200 übertragen. Im zweiten Kommunikationsendgerät 200 wird das empfangene Signal als akustisches Signal 330 an den Lautsprecher 220 des zweiten Kommunikationsendgerätes 200 weitergeleitet. Zuvor wird es jedoch sowohl der akustischen-Echo-Steuerung 600 als erstes Eingabesignal 610 zugeführt, als auch dem Feedbackschleifen-Detektor 400. In diesem Szenario sind in den Feedbackschleifen-Detektor 400 des zweiten Kommunikationsendgerätes 200 sowohl die Vorrichtung für das Ermitteln des Vorliegens einer akustischen Feedbackschleife 320 integriert, als auch die Vorrichtung zur Reduzierung der Signalintensität am Lautsprecher 220 des zweiten Kommunikationsendgerätes 200 für den Fall, dass das Vorliegen einer akustischen Feedbackschleife 320ermittelt wurde.The user 900 language is received as an acoustic signal 330 from the microphone 110 of the first communication terminal 100 and transmitted via the radio-based network 230 to the second communication terminal 200. In the second communication terminal 200, the received signal is forwarded as an acoustic signal 330 to the loudspeaker 220 of the second communication terminal 200. Prior to this, however, it is applied to both the acoustic echo controller 600 as the first input signal 610 and the feedback loop detector 400. In this scenario, the feedback loop detector 400 of the second communication terminal 200 includes both the device for detecting the presence of an acoustic signal Feedback loop 320 integrated, as well as the device for reducing the signal intensity at the speaker 220 of the second communication terminal 200 in the event that the presence of an acoustic feedback loop 320 has been determined.

Das ggfs. entsprechend Signaltechnisch reduzierte, akustische Signal 330 wird dann am Lautsprecher 220 des zweiten Kommunikationsendgerätes 200 ausgegeben.The optionally acoustically reduced acoustic signal 330 is then output at the loudspeaker 220 of the second communication terminal 200.

Dabei kann ein akustisches Echo 350 zwischen diesem Lautsprecher 220 und dem Mikrofon 210 des zweiten Kommunikationsendgerätes 200 entstehen. Das vom diesem Mikrofon 210 aufgenommene akustische Signal enthält daher ggfs. das akustische Echo 350 und wird der akustischen-Echo-Steuerung 600 als zweites Eingabesignal 610 zugeführt, um das vom Mikrofon 210 aufgenommene akustische Signal zu filtern und es als um das akustische Echo 350 bereinigtes Signal 640 über das funkbasierte Netzwerk 230 an das erste Kommunikationsendgerät 100 zu senden.In this case, an acoustic echo 350 may arise between this loudspeaker 220 and the microphone 210 of the second communication terminal 200. The acoustic signal received by this microphone 210 may therefore include the acoustic echo 350 and is supplied to the acoustic echo controller 600 as a second input signal 610 to filter the acoustic signal picked up by the microphone 210 and to be corrected for the acoustic echo 350 Signal 640 via the radio-based network 230 to the first communication terminal 100 to send.

Das vom Lautsprecher 220 des zweiten Kommunikationsendgerätes 200 ausgegebene akustische Signal kann jedoch, z.B. über Reflexion im Raum 340, wieder an das Mikrofon zurückgelangen und dadurch für eine Feedbackschleife 320(deswegen ja als Weg beschrieben) zwischen den beiden Kommunikationsendgeräten 100, 200 sorgen.However, the acoustic signal output by the speaker 220 of the second communication terminal 200 may, for example via reflection in the space 340, return to the microphone and thereby provide a feedback loop 320 (therefore described as a path) between the two communication terminals 100, 200.

Da jedoch das akustische Signal signaltechnisch im zweiten Kommunikationsendgerät 200 bei Detektion einer Feedbackschleife 320 reduziert wurde bevor es vom Lautsprecher 220 des zweiten Kommunikationsendgerätes 200 ausgegeben wird, wird das weitere Aufschwingen einer Feedbackschleife 320 im Wesentlichen verhindert.However, since the acoustic signal has been signal-reduced in the second communication terminal 200 upon detection of a feedback loop 320 before it is output by the loudspeaker 220 of the second communication terminal 200, further oscillation of a feedback loop 320 is substantially prevented.

Claims (3)

  1. Method for suppressing acoustic feedbacks between communication terminals for mobile voice and/or data communication in a radio-based network comprising at least the following method steps:
    - coupling (310) signals between a microphone (110) and a loudspeaker (220), the microphone (110) being a component of a first communication terminal (100), and the loudspeaker (220) being a component of a second communication terminal (200),
    - determining the presence of an acoustic feedback loop (320) between the first communication terminal (100) and the second communication terminal (200) by means of a feedback loop detector (400),
    - wherein the acoustic feedback loop (320) is due to feedback (340) of a first acoustic signal (330) in the microphone (110) of the first communication terminal (100) via the loudspeaker (220) of the second communication terminal (200),
    - reducing the signal intensity between the microphone (110) of the first communication terminal (100) and the loudspeaker (220) of the second communication terminal (200) by means of a signal amplification controller in the case where the presence of an acoustic feedback loop (320) has been determined,
    - attenuating an acoustic echo (350) between the loudspeaker (220) of the second communication terminal (200) and a second microphone (210) by means of an acoustic echo controller (600),
    wherein the second microphone (210) is a component of the second communication terminal (200),
    wherein the acoustic echo controller (600) receives as the first input signal (610) the first acoustic signal (330) of the microphone (110) of the first communication terminal (100), received from the second communication terminal (200), and receives as the second input signal (620) a second acoustic signal received from the second microphone (210),
    wherein the second acoustic signal contains the acoustic echo (350) and wherein the acoustic echo controller (600) outputs an output signal (640) filtered by the acoustic echo (350),
    wherein the acoustic echo (350) arises from feedback of the first acoustic signal (330), received from the second communication terminal (200), from the loudspeaker (220) to the second microphone (210),
    - determining the probability of the occurrence of the acoustic feedback loop (320) between the first communication terminal (100) and the second communication terminal (200) by the feedback loop detector (400),
    wherein the method step for determining the probability of the occurrence of the acoustic feedback loop (320) between the first communication terminal (100) and the second communication terminal (200) by the feedback loop detector (400) comprises at least:
    - estimating the probability of the occurrence of the acoustic feedback loop (320) by including a near-field signal and a far-field signal,
    wherein the near-field signal corresponds to an acoustic echo (350) which arises by feedback (370) of the first acoustic signal (330), received from the second communication terminal (200), from the loudspeaker (220) to the second microphone (210), and wherein the far-field signal corresponds to the feedback (340) of the first acoustic signal (330) in the microphone (110) of the first communication terminal (100) via the loudspeaker (220) of the second communication terminal (200) and by additionally adding the coherence between the near-field signal and the far-field signal.
  2. Method for suppressing acoustic feedbacks between communication terminals according to Claim 1, wherein the feedback loop detector (400) and the signal amplification controller are a component of the second communication terminal (200), and
    wherein the signal amplification controller carries out the signal amplification of the first acoustic signal (330), received from the second communication terminal (200), at the loudspeaker (220) of the second communication terminal (200).
  3. Method for suppressing acoustic feedbacks between communication terminals according to one of the preceding claims, wherein
    the first communication terminal (100) and the second communication terminal (200) are connected to one another via a communication and/or data network which supports the DECT standard.
EP11155062.0A 2011-02-18 2011-02-18 Acoustic feedback suppression for communication terminals Active EP2490460B1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP11155062.0A EP2490460B1 (en) 2011-02-18 2011-02-18 Acoustic feedback suppression for communication terminals

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP11155062.0A EP2490460B1 (en) 2011-02-18 2011-02-18 Acoustic feedback suppression for communication terminals

Publications (2)

Publication Number Publication Date
EP2490460A1 EP2490460A1 (en) 2012-08-22
EP2490460B1 true EP2490460B1 (en) 2013-11-20

Family

ID=44080213

Family Applications (1)

Application Number Title Priority Date Filing Date
EP11155062.0A Active EP2490460B1 (en) 2011-02-18 2011-02-18 Acoustic feedback suppression for communication terminals

Country Status (1)

Country Link
EP (1) EP2490460B1 (en)

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002101728A1 (en) * 2001-06-11 2002-12-19 Lear Automotive (Eeds) Spain, S.L. Method and system for suppressing echoes and noises in environments under variable acoustic and highly fedback conditions
FR2856183A1 (en) * 2003-06-13 2004-12-17 France Telecom Echo control device for e.g. general packet radio service network, has unit modifying signal captured from communication device based on information representing diffused signal and coupling separating speaker from microphone
US7664275B2 (en) * 2005-07-22 2010-02-16 Gables Engineering, Inc. Acoustic feedback cancellation system

Also Published As

Publication number Publication date
EP2490460A1 (en) 2012-08-22

Similar Documents

Publication Publication Date Title
DE69635500T2 (en) Method and device for detecting a nearby speech signal
DE112009002617B4 (en) Optional switching between multiple microphones
DE60203282T2 (en) PHONE UNIT
DE60024815T2 (en) SYSTEM AND METHOD FOR RECOGNIZING A NEAR SPEAKER BY SPECTRUM ANALYSIS
DE69634841T2 (en) Method and apparatus for echo cancellation
EP1456839B1 (en) Method and device for the suppression of periodic interference signals
DE69929526T2 (en) TELEPHONE APPARATUS WITH VOLUME CONTROL
DE69830976T2 (en) Adaptive interference suppression
EP3375204B1 (en) Audio signal processing in a vehicle
DE112012005782T5 (en) Reverberation suppression device
DE19805942C1 (en) Method for improving the acoustic return loss in hands-free equipment
EP1155561B1 (en) Method and device for suppressing noise in telephone devices
EP1920589A1 (en) Apparatus for position-dependent control
EP1126687A2 (en) Method for coordinated echo and/or noise reduction
EP0874513A2 (en) Device for feedback suppression
DE102008046040A1 (en) Method for operating a hearing device with directivity and associated hearing device
EP2490460B1 (en) Acoustic feedback suppression for communication terminals
DE102014210760B4 (en) operation of a communication system
EP2490427B1 (en) Acoustic coupling recognition between communication terminals in a conference call
DE69433659T2 (en) Device and method for echo attenuation
EP1062487A1 (en) Microphone device for speech recognition in variable spatial conditions
DE19935587A1 (en) Detection of echo state in duplex transmission e.g. when using mobile phone system, is achieved by monitoring adaptive filter coefficient update, which reveals phantom signal presence on exceeding threshold
DE102018117558A1 (en) ADAPTIVE AFTER-FILTERING
DE102018213367B4 (en) Method and telephony device for noise suppression of a system-generated audio signal during a telephone call and a vehicle with the telephony device
DE102018117556B4 (en) SINGLE CHANNEL NOISE REDUCTION

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

17P Request for examination filed

Effective date: 20130222

GRAP Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOSNIGR1

INTG Intention to grant announced

Effective date: 20130612

GRAS Grant fee paid

Free format text: ORIGINAL CODE: EPIDOSNIGR3

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

Free format text: NOT ENGLISH

REG Reference to a national code

Ref country code: CH

Ref legal event code: EP

REG Reference to a national code

Ref country code: AT

Ref legal event code: REF

Ref document number: 642235

Country of ref document: AT

Kind code of ref document: T

Effective date: 20131215

REG Reference to a national code

Ref country code: IE

Ref legal event code: FG4D

Free format text: LANGUAGE OF EP DOCUMENT: GERMAN

REG Reference to a national code

Ref country code: DE

Ref legal event code: R096

Ref document number: 502011001663

Country of ref document: DE

Effective date: 20140116

REG Reference to a national code

Ref country code: NL

Ref legal event code: VDEP

Effective date: 20131120

REG Reference to a national code

Ref country code: LT

Ref legal event code: MG4D

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: FI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

Ref country code: IS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20140320

Ref country code: SE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

Ref country code: HR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

Ref country code: LT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

Ref country code: NO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20140220

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: LV

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

Ref country code: ES

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

Ref country code: RS

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: PT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20140320

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: EE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 502011001663

Country of ref document: DE

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CZ

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

Ref country code: RO

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

Ref country code: SK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

Ref country code: PL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

BERE Be: lapsed

Owner name: GIGASET COMMUNICATIONS G.M.B.H.

Effective date: 20140228

PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MC

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

Ref country code: DK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

Ref country code: LU

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20140218

REG Reference to a national code

Ref country code: CH

Ref legal event code: PL

26N No opposition filed

Effective date: 20140821

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: CH

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20140228

Ref country code: LI

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20140228

REG Reference to a national code

Ref country code: IE

Ref legal event code: MM4A

REG Reference to a national code

Ref country code: DE

Ref legal event code: R097

Ref document number: 502011001663

Country of ref document: DE

Effective date: 20140821

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: BE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20140228

Ref country code: IE

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20140218

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SI

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: IT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

REG Reference to a national code

Ref country code: DE

Ref legal event code: R082

Ref document number: 502011001663

Country of ref document: DE

Representative=s name: MICHALSKI HUETTERMANN & PARTNER PATENTANWAELTE, DE

Ref country code: DE

Ref legal event code: R081

Ref document number: 502011001663

Country of ref document: DE

Owner name: GIGASET COMMUNICATIONS GMBH, DE

Free format text: FORMER OWNER: GIGASET COMMUNICATIONS GMBH, 81379 MUENCHEN, DE

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 6

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: SM

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20140221

Ref country code: CY

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

Ref country code: BG

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: TR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

Ref country code: HU

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT; INVALID AB INITIO

Effective date: 20110218

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 7

REG Reference to a national code

Ref country code: AT

Ref legal event code: MM01

Ref document number: 642235

Country of ref document: AT

Kind code of ref document: T

Effective date: 20160218

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AT

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20160218

REG Reference to a national code

Ref country code: FR

Ref legal event code: PLFP

Year of fee payment: 8

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: MK

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: AL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20131120

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: FR

Payment date: 20230221

Year of fee payment: 13

PGFP Annual fee paid to national office [announced via postgrant information from national office to epo]

Ref country code: GB

Payment date: 20230220

Year of fee payment: 13

Ref country code: DE

Payment date: 20230216

Year of fee payment: 13

P01 Opt-out of the competence of the unified patent court (upc) registered

Effective date: 20230527