Voice activity detection and silence suppression in a packet network

• US 7,272,552 B1
• Filed: 12/27/2002
• Issued: 09/18/2007
• Est. Priority Date: 12/27/2002
• Status: Expired due to Fees

• Current Assignee: Nuance Communications, Inc. (Microsoft Corporation)
• Original Assignee: AT&T Corporation (AT&T, Inc.)
• Inventors: Rosenbluth, Joshua Hal, James, James H
• Primary Examiner(s): Knepper; David D.
• Application Number:
  US10/330,957
• Time in Patent Office: 1,726 Days
• Field of Search: None
• US Class Current: 704/215
• CPC Class Codes: G10L 19/012 Comfort noise or silence coding
• CPC Class Codes: G10L 19/167 Audio streaming, i.e. formatting and decoding of an encoded audio signal representation into a data stream for transmission or storage purposes
• CPC Class Codes: G10L 25/78 Detection of presence or absence of voice signals switching of direction of transmission by voice frequency in two-way loud-speaking telephone systems H04M9/10
• CPC Class Codes: H04J 3/17 in which the transmission channel allotted to a first user may be taken away and re-allotted to a second user if the first user becomes inactive, e.g. TASI speech analysis or identification G10L
• CPC Class Codes: H04L 65/1059 End-user terminal functionalities specially adapted for real-time communication
• CPC Class Codes: H04L 65/80 Responding to QoS

Abstract

The present invention is a system and method that improves upon voice activity detection by packetizing actual noise signals, typically background noise. In accordance with the present invention an access network receives an input voice signal (including noise) and converts the input voice signal into a packetized voice signal. The packetized voice signal is transmitted via a network to an egress network. The egress network receives the packetized voice signal, converts the packetized voice signal into an output voice signal, and outputs the output voice signal. The egress network also extracts and stores noise packets from the received packetized voice signal and converts the packetized noise signal into an output noise signal. When the access network ceases to receive the input voice signal while the call is still ongoing, the access network instructs the egress network to continually output the output noise signal.

Claims

1. A silence suppression system for a call, comprising:

an access gateway including an access silence suppressor, wherein the access gateway receives an input voice signal and a background noise signal and converts the input voice signal into a packetized voice signal and the background noise signal into a packetized noise signal; and

an egress gateway that receives the packetized voice signal and the packetized noise signal, outputs an output voice signal converted from the packetized voice signal and extracts and stores noise packets from the received packetized noise signal,

wherein when the access gateway ceases to receive the input voice signal while the call is still ongoing, the access gateway instructs the egress gateway to continually output an output noise signal generated from the stored noise packets.

2. The system of claim 1, wherein the access gateway ceases to receive the input voice signal for a predefined hang-over time prior to instructing the egress gateway to continually output the output noise signal.

3. The system of claim 1, wherein the system uses Voice over Internet Protocol (VoIP) technology.

4. The system of claim 1, wherein the system uses Voice over Frame technology.

5. The system of claim 1, wherein the system uses Voice over ATM technology.

6. The system of claim 1, wherein the input voice signal is received from a speaking party and the output voice signal and output noise signal are output to a listening party.

7. A silence suppression system for a call, comprising:

first means for receiving an input voice signal and a background noise signal and converting the input voice signal into a packetized voice signal and converting the noise signal into a packetized noise signal; and

second means for receiving, converting the packetized voice signal into an output voice signal and receiving the packetized noise signal into an output noise signal,

wherein the second means includes an egress silence suppression means,

wherein the second means further extracts and stores noise packets from the received packetized voice signal and converts the packetized noise signal into an output noise signal, and

wherein when the first means ceases to receive the input voice signal while the call is still ongoing, first means instructs the second means to continually output the output noise signal.

8. The system of claim 7, wherein the first means ceases to receive the input voice signal for a predefined hang-over time prior to instructing the second means to continually output the output noise signal.

9. The system of claim 7, wherein the system uses Voice over Internet Protocol (VoIP) technology.

10. The system of claim 7, wherein the system uses Voice over Frame technology.

11. The system of claim 7, wherein the system uses Voice over ATM technology.

12. A method for silence suppression during an ongoing call, the method comprising:

receiving an input voice signal and a background noise signal by an access gateway and converting the input voice signal into a packetized voice signal and the noise signal into a packetized noise signal;

transmitting the packetized voice signal and the packetized noise signal from the access gateway to an egress gateway via a network;

receiving the packetized voice signal and the packetized noise signal by the egress gateway and converting the packetized voice signal into an output voice signal;

extracting and storing by the egress gateway noise packets from the received packetized noise signal and converting the packetized noise signal into an output noise signal; and

upon ceasing to receive the input voice signal by the access gateway while the call is still ongoing, instructing the egress gateway to continually output the output noise signal.

13. The method of claim 12, wherein the ceasing step occurs when the access gateway receives no input voice signal for a predefined hang-over time.

14. The method of claim 12, wherein the method uses Voice over Internet Protocol (VoIP) technology.

15. The method of claim 12, wherein the method uses Voice over Frame technology.

16. The method of claim 12, wherein the method uses Voice over ATM technology.