Wireless telephone with multiple microphones and multiple description transmission

• US 20060154623A1
• Filed: 08/31/2005
• Published: 07/13/2006
• Est. Priority Date: 12/22/2004
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Bennett, James, Chen, Juin-Hwey
• Granted Patent: US 8,509,703 B2
• Time in Patent Office: Days
• US Class Current: 455/116
• CPC Class Codes: H04M 1/03 Constructional features of telephone transmitters or receivers, e.g. telephone hand-sets
• CPC Class Codes: H04M 9/08 Two-way loud-speaking telephone systems with means for conditioning the signal, e.g. for suppressing echoes for one or both directions of traffic
• CPC Class Codes: H04M 9/082 using echo cancellers echo cancellers per se H04B3/23

Abstract

The present invention is directed to a multiple description transmission system that provides redundancy to combat transmission channel impairments. The multiple description transmission system includes a first and second wireless telephone. The first wireless telephone includes the following: an array of microphones, wherein each microphone in the array of microphones is configured to receive voice input from a user and to produce a voice signal corresponding thereto; an encoder coupled to the microphone array and configured to encode each of the voice signals; and a transmitter coupled to the encoder and configured to transmit each of the encoded voice signals. The second wireless telephone includes the following: a receiver configured to receive the transmitted signals; a decoder coupled to the receiver and configured to decode the signals received by the receiver, thereby producing an output signal; and a loudspeaker that receives the output signal and produces a pressure sound wave corresponding thereto.

Claims

1. A wireless telephone, comprising:

an array of microphones, each microphone in the array configured to receive voice input from a user and to produce a voice signal corresponding thereto;

an encoder configured to encode each of the voice signals; and

a transmitter configured to transmit each of the encoded voice signals.

2. The wireless telephone of claim 1,

wherein the encoder is configured to encode one of the voice signals at a first bit rate and each of the other voice signals at a bit rate different from the first bit rate.

3. A wireless telephone, comprising:

a receiver configured to receive multiple versions of a voice signal, each version being produced from a microphone in a microphone array of a second wireless telephone;

a decoder coupled to the receiver and configured to decode the multiple versions of the voice signal to produce an output signal; and

a speaker configured to receive the output signal and produce a sound pressure wave corresponding thereto.

4. The wireless telephone of claim 3,

wherein the decoder is further configured to time-align the multiple versions of the voice signal and to combine the time-aligned versions to produce the output signal, whereby the output signal has a higher signal-to-noise ratio than any of the multiple versions of the voice signal.

5. The wireless telephone of claim 3, wherein:

the decoder is further configured to detect a direction of arrival (DOA) of a sound wave emanating from the mouth of a user of the second wireless telephone based on the multiple versions of the voice signal and to adaptively combine the multiple versions based on the DOA to produce the output signal; and

the decoder is still further configured to adaptively combine the multiple versions based on the DOA to effectively steer a maximum sensitivity angle of the microphone array of the second wireless telephone so that the mouth of the user of the second wireless telephone is within the maximum sensitivity angle, wherein the maximum sensitivity angle is defined as an angle within which a sensitivity of the microphone array is above a threshold.

6. The wireless telephone of claim 3, wherein,

for each voice frame of the multiple versions of the voice signal, the decoder is further configured to estimate channel impairments and decode a version of the voice signal with the least channel impairments, whereby the decoded version is used as the output signal for the respective voice frames.

7. The wireless telephone of claim 3, wherein:

for each voice frame of the multiple versions of the voice signals, the decoder is further configured to set a threshold of channel impairments and dynamically discard each version of the voice signal having a channel impairment worse than the threshold; and

the decoder is still further configured to time-align and combine the received signals of the non-discarded versions of the voice signal to produce the output signal, whereby the output signal has a higher signal-to-noise ratio than any of the multiple versions of the voice signal received by the receiver.

8. The wireless telephone of claim 3, wherein:

for each voice frame of the multiple versions of the voice signals, the decoder is further configured to set a threshold of channel impairments and dynamically discard each version of the voice signal having a channel impairment worse than the threshold; and

the decoder is still further configured to detect a direction of arrival (DOA) of a sound wave emanating from the mouth of a user of the second wireless telephone based on the voice frames of the non-discarded versions of the voice signal and to adaptively combine the voice frames of the non-discarded versions based on the DOA to produce the output signal; and

the decoder is further configured to adaptively combine the voice frames of the non-discarded versions based on the DOA to effectively steer a maximum sensitivity angle of the microphone array of the second wireless telephone so that the mouth of the user of the second wireless telephone is within the maximum sensitivity angle, wherein the maximum sensitivity angle is defined as an angle within which a sensitivity of the microphone array is above a threshold.

9. The wireless telephone of claim 3,

wherein, prior to the receipt by the receiver, the multiple versions of the voice signal are encoded and transmitted at different bit rates by the second wireless telephone.

10. The wireless telephone of claim 9, wherein:

prior to receipt by the receiver, one of the versions of the voice signal is encoded and transmitted at a first bit rate over a main channel and each other version is encoded and transmitted at a bit rate different from the first bit rate over a corresponding auxiliary channel; and

for each voice frame of the multiple versions of the voice signal received by the receiver, the decoder is further configured to estimate channel impairments, and if (i) the main channel is corrupted by channel impairments, and (ii) at least one auxiliary channel is not corrupted by channel impairments, to decode an auxiliary channel to produce the output signal.

11. The wireless telephone of claim 9, wherein:

prior to receipt by the receiver, one of the versions of the voice signal is encoded and transmitted at a first bit rate over a main channel and each other version is encoded and transmitted at a bit rate different from the first bit rate over a corresponding auxiliary channel; and

for each voice frame of the multiple versions of the voice signal received by the receiver, the decoder is further configured to estimate channel impairments, and if (i) side information corresponding to the main channel is corrupted by channel impairments, and (ii) side information corresponding to at least one auxiliary channel is not corrupted, to use both the main channel and at least one auxiliary channel to improve performance of a frame erasure concealment algorithm in the production of the output signal.

12. A multiple-description wireless-communication transmission system, comprising:

a first wireless telephone comprising

an array of microphones, each microphone in the array configured to receive voice input from a user and to produce a voice signal corresponding thereto,

an encoder coupled to the array of microphones and configured to encode each of the voice signals, and

a transmitter coupled to the encoder and configured to transmit each of the encoded voice signals; and

a second wireless telephone comprising

a receiver configured to receive the transmitted signals,

a decoder coupled to the receiver and configured to decode the signals received by the receiver, thereby producing an output signal, and

a speaker configured to receive the output signal and produce a sound pressure wave corresponding thereto.

13. The system of claim 12,

wherein the decoder is further configured to time-align the signals received by the receiver and to combine the time-aligned signals to produce the output signal, whereby the output signal has a higher signal-to-noise ratio than any of the transmitted signals received by the receiver.

14. The system of claim 12, wherein:

the decoder is further configured to (i) detect a direction of arrival (DOA) of a sound wave emanating from the mouth of a user of the first wireless telephone based on the signals received by the receiver of the second wireless telephone and (ii) adaptively combine the received signals based on the DOA to produce the output signal; and

the decoder is still further configured to adaptively combine the received signals based on the DOA to effectively steer a maximum sensitivity angle of the microphone array of the first wireless telephone so that the mouth of the user of the first wireless telephone is within the maximum sensitivity angle, wherein the maximum sensitivity angle is defined as an angle within which a sensitivity of the microphone array is above a threshold.

15. The system of claim 12,

wherein, for each voice frame of the signals received by the receiver, the decoder is further configured to estimate channel impairments and decode a signal received by the receiver with the least channel impairments, thereby producing the output signal for the respective voice frames.

16. The system of claim 12, wherein:

for each voice frame of the signals received by the receiver, the decoder is further configured to estimate channel impairments and dynamically discard each received signal having a channel impairment worse than a threshold; and

the decoder is further configured to time-align and combine the voice frames of the non-discarded signals to produce the output signal, whereby the output signal has a higher signal-to-noise ratio than any of the transmitted signals received by the receiver.

17. The system of claim 12, wherein:

for each voice frame of the signals received by the receiver, the decoder is further configured to estimate channel impairments and dynamically discard each received signal having a channel impairment worse than a threshold; and

the decoder is further configured to detect a direction of arrival (DOA) of a sound wave emanating from the mouth of a user of the first wireless telephone based on the voice frames of the non-discarded signals and to adaptively combine the voice frames of the non-discarded signals based on the DOA to produce the output signal; and

the decoder is still further configured to adaptively combine the voice frames of the non-discarded signals based on the DOA to effectively steer a maximum sensitivity angle of the microphone array of the first wireless telephone so that the mouth of the user of the first wireless telephone is within the maximum sensitivity angle, wherein the maximum sensitivity angle is defined as an angle within which a sensitivity of the microphone array is above a threshold.

18. The system of claim 12,

wherein the encoder is configured to encode the voice signals at different bit rates.

19. The system of claim 18, wherein:

the encoder is configured to encode one of the voice signals at a first bit rate for transmission over a main channel and each other voice signal at a bit rate different from the first bit rate for transmission over a corresponding auxiliary channel; and

for each voice frame of the signals received by the receiver, the decoder of the second wireless telephone is further configured to estimate channel impairments, and if (i) the main channel is corrupted by channel impairments, and (ii) at least one auxiliary channel is not corrupted by channels impairments, to decode an auxiliary channel.

20. The system of claim 18, wherein:

the encoder is configured to encode one of the voice signals at a first bit rate for transmission over a main channel and each other voice signal at a bit rate different from the first bit rate for transmission over a corresponding auxiliary channel; and

for each voice frame of the signals received by the receiver, the decoder is further configured to estimate channel impairments, and if (i) side information corresponding to the main channel is corrupted by channel impairments, and (ii) side information corresponding to at least one auxiliary channel is not corrupted by channel impairments, to use both the main channel and one of the auxiliary channels to improve performance of a frame erasure concealment algorithm in the production of the output signal.