Method for discontinuous transmission and accurate reproduction of background noise information

• US 8,102,872 B2
• Filed: 05/05/2005
• Issued: 01/24/2012
• Est. Priority Date: 02/01/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Spindola, Serafin Diaz, Black, Peter J., Kapoor, Rohit
• Primary Examiner(s): Ngo, Ricky
• Assistant Examiner(s): Kao, Wei-Po
• Application Number:
  US11/123,478
• Publication Number:
  US 20060171419A1
• Time in Patent Office: 2,455 Days
• Field of Search: 370/230, 370/235, 370/320, 370/335, 370/338, 370/342, 370/441, 370/450, 370/454, 370/459, 370/477
• US Class Current: 370/450
• CPC Class Codes: G10L 19/012 Comfort noise or silence coding
• CPC Class Codes: G10L 19/24 Variable rate codecs, e.g. for generating different qualities using a scalable representation such as hierarchical encoding or layered encoding

Abstract

The present invention comprises a method of communicating background noise comprising the steps of transmitting background noise, blanking subsequent background noise data rate frames used to communicate the background noise, receiving the background noise and updating the background noise. In another embodiment, the present invention comprises an apparatus for communicating background noise comprising a vocoder, at least one smart blanking apparatus operably connected to the vocoder, a de jitter buffer operably connected to the smart blanker; and a network stack operably connected to the input of the de jitter buffer and the an output of the smart blanking apparatus.

Claims

1. A method of communicating background noise between a first device and a second device, each device including circuitry for transmitting data to and receiving data from the other device, the method comprising:

generating a set of frames comprising a first frame and one or more subsequent background noise frames, the first frame used to communicate the background noise;

transmitting from the first device the background noise by using the first frame, the transmitting comprising a first data rate, wherein the transmitting further comprises;

comparing, based on a sum of absolute differences of elements of codebook entries for said plurality of background noise frames, a spectrum of a particular background noise frame to an average spectrum of a plurality of background noise frames; and

transmitting an update background noise frame if a difference of the spectrums exceeds a spectrum threshold;

determining if subsequent background noise frames are stable or transitory from voice;

blanking at least one of the subsequent background noise frames based on the determination, wherein blanking comprises not transmitting a frame;

transmitting a keep alive packet before subsequent background noise frames are blanked for longer than a threshold time;

receiving a background noise frame from the second device; and

updating a background noise associated with the second device.

2. The method of communicating background noise according to claim 1, further comprising filtering the background noise frames.

3. The method of communicating background noise according to claim 2, further comprising playing an erasure if no frame is received.

4. The method of communicating background noise according to claim 3, wherein said erasure is played less than or equal to 50 percent of the time.

5. The method of communicating background noise according to claim 1, further comprising playing background noise, wherein playing background noise comprises:

outputting white noise in the form of a random sequence of numbers, and

extracting a frequency characteristic of said white noise.

6. The method according to claim 1, further comprising waiting until at least one of said background noise frames has been sent before sending an update background noise frame, whereby a stable background noise frame is transmitted.

7. The method according to claim 1, further comprising waiting until 40 to 100 ms after last transitory background noise frames have been sent before sending an update background noise frame, whereby a stable background noise frame is transmitted.

8. The method of communicating background noise according to claim 1, further comprising initializing an encoder and a decoder, wherein initializing an encoder and a decoder comprises:

setting a state of said encoder to a voice state;

setting a state of said decoder to a silence state; and

setting a prototype to a 1/8 data rate frame.

9. The method of communicating background noise according to claim 1, further comprising blending the background noise.

10. The method of communicating background noise according to claim 9, wherein blending comprises changing said background noise gradually from a prior update value to a new update value.

11. The method of communicating background noise according to claim 1, further comprising playing an erasure if said background noise frame is not received.

12. The method of communicating background noise according to claim 11, wherein said erasure is played less than or equal to 50 percent of the time.

13. The method of communicating background noise according to claim 1, wherein updating the background noise comprises transmitting an update background noise frame having at least one codebook entry.

14. The method of communicating background noise according to claim 1, wherein receiving the background noise, comprises:

receiving a frame;

determining if said frame is a voice frame;

determining if a state is a voice state if said frame is said voice frame;

playing said frame if said state is said voice state and said frame is said voice frame;

checking if said frame is a silence frame if said frame is not said voice frame;

checking if said state is a silence state if said frame is said silence frame;

transitioning to said silence state and playing said frame if said frame is said silence frame and said state is not said silence state;

generating an update and playing said update if said frame is said silence frame and said state is said silence state;

checking if said state is said silence state if said frame not said voice frame or said silence frame;

playing a prototype frame if said state is said silence state and said frame is not said voice frame or said silence frame;

checking if N consecutive erasures have been sent if said state is not said silence state and said frame is not said voice frame or said silence frame;

playing an erasure if N consecutive erasures have not been sent, said state is not said silence state and said frame is not said voice frame or said silence frame; and

transitioning to said silence state and playing said prototype frame if N consecutive erasures have been sent, said state is not said silence state and said frame is not said voice frame or said silence frame.

15. A method of operating a transmitter to communicate background noise information to a receiver over a communication channel, said method comprising:

receiving a frame;

determining if said frame is a silence frame;

transitioning to an active state and transmitting said frame if said frame is not said silence frame;

determining if a state is a silence state if said frame is said silence frame;

transitioning to said silence state and sending said silence frame to a receiver if said frame is said silence frame and said state is not in said silence state;

determining if said frame is stable or transitory from voice, if said frame is said silence frame and said state is in said silence state;

updating statistics and determining if an update was triggered if said frame is stable;

blanking silence frames based on whether they are stable or transitory from voice;

building and sending a prototype frame if said update was triggered; and

, wherein the triggering comprises;

comparing, based on a sum of absolute differences of elements of codebook entries for said plurality of background noise frames, a spectrum of a particular background noise frame to an average spectrum of a plurality of background noise frames; and

transmitting the prototype frame if a difference of the spectrums exceeds a spectrum threshold;

transmitting a keep alive packet before subsequent background noise frames are blanked for longer than a threshold time.

16. The method of communicating background noise according to claim 15, wherein transmitting the background noise further comprises transmitting transitory background noise frames if said frame is not stable.

17. The method of communicating background noise according to claim 15, wherein triggering further comprises:

comparing an energy of a particular background noise frame to an average energy of a plurality of said background noise frames; and

transmitting the prototype frame if a difference of the energies exceeds an energy threshold and the difference of spectrums exceeds the spectrum threshold.

18. The method of communicating background noise according to claim 17, wherein said threshold is equal to or greater than 1 db.

19. The method of communicating background noise according to claim 17, wherein transmitting the prototype frame comprises transmitting at least one codebook entry.

20. The method of communicating background noise according to claim 19, wherein said at least one code book entry comprises at least one energy codebook entry, and at least one spectral code book entry.

21. The method of communicating background noise according to claim 20, wherein said update comprises a most frequently used codebook entry.

22. The method of communicating background noise according to claim 15, wherein said threshold is equal to or greater than 40 percent.

23. The method of communicating background noise according to claim 15, wherein transmitting the prototype frame comprises transmitting at least one codebook entry.

24. An apparatus for communicating background noise, comprising:

a processor;

memory in electronic communication with the processor;

instructions stored in the memory, the instructions being executable by the processor to;

generate a set of frames comprising a first frame and one or more subsequent background noise frames, the first frame used to communicate the background noise;

transmit from the first device the background noise by using the first frame, the transmitting comprising a first data rate, wherein the transmitting further comprises;

comparing, based on a sum of absolute differences of elements of codebook entries for said plurality of background noise frames, a spectrum of a particular background noise frame to an average spectrum of a plurality of background noise frames; and

transmitting an update background noise frame if a difference of the spectrums exceeds a spectrum threshold;

determine if subsequent background noise frames are stable or transitory from voice;

blank at least one of the subsequent background noise frames based on the determination, wherein blanking comprises not transmitting a frame;

transmit a keep alive packet before subsequent background noise frames are blanked for longer than a threshold time;

receive a background noise frame from the second device; and

update a background noise associated with the second device.

25. An apparatus for communicating background noise, comprising:

means for generating a set of frames comprising a first frame and one or more subsequent background noise frames, the first frame used to communicate the background noise;

means for transmitting from the first device the background noise by using the first frame, the transmitting comprising a first data rate, wherein the transmitting further comprises;

comparing, based on a sum of absolute differences of elements of codebook entries for said plurality of background noise frames, a spectrum of a particular background noise frame to an average spectrum of a plurality of background noise frames; and

transmitting an update background noise frame if a difference of the spectrums exceeds a spectrum threshold;

means for determining if subsequent background noise frames are stable or transitory from voice;

means for blanking at least one of the subsequent background noise frames based on the determination, wherein blanking comprises not transmitting a frame;

means for transmitting a keep alive packet before subsequent background noise frames are blanked for longer than a threshold time;

means for receiving a background noise frame from the second device; and

means for updating a background noise associated with the second device.

26. A non-transitory computer-readable medium comprising executable instructions for:

generating a set of frames comprising a first frame and one or more subsequent background noise frames, the first frame used to communicate the background noise;

transmitting from the first device the background noise by using the first frame, the transmitting comprising a first data rate, wherein the transmitting further comprises;

comparing, based on a sum of absolute differences of elements of codebook entries for said plurality of background noise frames, a spectrum of a particular background noise frame to an average spectrum of a plurality of background noise frames; and

transmitting an update background noise frame if a difference of the spectrums exceeds a spectrum threshold;

determining if subsequent background noise frames are stable or transitory from voice;

blanking at least one of the subsequent background noise frames based on the determination, wherein blanking comprises not transmitting a frame;

transmitting a keep alive packet before subsequent background noise frames are blanked for longer than a threshold time;

receiving a background noise frame from the second device; and

updating a background noise associated with the second device.