Transmission of comfort noise parameters during discontinuous transmission

• US 20010046843A1
• Filed: 06/11/2001
• Published: 11/29/2001
• Est. Priority Date: 11/14/1996
• Status: Active Grant

• Current Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Original Assignee: Nokia Mobile Phones UK Limited (Nokia Corporation)
• Inventors: Alanara, Seppo, Kapanen, Pekka
• Granted Patent: US 6,816,832 B2
• Time in Patent Office: Days
• US Class Current: 455/95
• CPC Class Codes: G10L 19/012 Comfort noise or silence coding

Abstract

A comfort noise block, that include a hangover period and comfort noise parameters, is transmitted in such a manner that it is not interrupted by other messages, such as FACCH messages. This is accomplished in a mobile station by a determination of whether any FACCH messages are required to be transmitted. If such FACCH messages exist, a further determination may be made as to which transmission can be made in the shortest time (i.e., the FACCH message or messages or the comfort noise parameters message), and this transmission is made first. In any event the comfort noise parameters block is transmitted without interruption. In a further embodiment of this invention the comfort noise parameters message is transmitted by being concatenated with another message, such as a neighbor channel measurement results message, so as to reduce overhead, conserve bandwidth, and reduce power consumption. An element of the comfort noise parameters message is a Random Excitation Spectral Control (RESC) information element, which is used in the decoder for improving the spectral content of the generated comfort noise so as to better match the background noise at the transmitter.

Claims

1. A method for transmitting a comfort noise (CN) block, the comfort noise block being comprised of a hangover period and comfort noise parameters, in a digital mobile terminal that operates in a discontinuous transmission (DTX) mode, comprising the steps of:

determining whether any control channel messages are required to be transmitted; and

if such control channel messages exist, grouping the control channel message or messages such that a comfort noise block can be scheduled for transmission without interruption.

2. A method as in

claim 1

, wherein the control channel messages are comprised of Fast Associated Control Channel (FACCH) messages.

3. A method as in

claim 1

, and further comprising steps of:

determining whether the control message or messages transmission or a comfort noise block transmission can be transmitted in the shortest period of time; and

transmitting the shortest transmission first, followed by the other transmission, wherein the comfort noise block transmission is transmitted without interruption.

4. A method as set forth in

claim 1

, and including a step of generating a Random Excitation Spectral Control (RESC) information element as a part of the comfort noise parameters, the RESC information element being used for improving a spectral content of generated comfort noise.

5. A mobile station operative with a base station, said mobile station comprising:

a transmitter;

an input speech transducer;

a voice activity detection (VAD) function coupled to said speech transducer; and

a controller having an input coupled to an output of said VAD function, to an output of said speech transducer, and to an input of said transmitter, said controller being responsive to said VAD function indicating an absence of user speech for initiating a Discontinuous Transmission (DTX) mode of operation and for transmitting at least one comfort noise (CN) block, the comfort noise block being comprised of a hangover period following a detected absence of speech and comfort noise parameters, said controller being operative for determining whether any control channel messages are required to be transmitted and, if such control channel messages exist, for insuring that a comfort noise block is transmitted without interruption by one or more of said control channel messages.

6. A mobile station as in

claim 5

, wherein the control channel messages are comprised of Fast Associated Control Channel (FACCH) messages.

7. A mobile station as in

claim 5

, wherein said controller is further operative to determine whether the control message or messages transmission or a comfort noise block transmission can be transmitted in the shortest period of time and, responsive to the determination, for transmitting the shortest transmission first, followed by the other transmission, wherein the comfort noise block transmission is transmitted without interruption.

8. A mobile station as set forth in

claim 5

, and further comprising a speech encoder operable for generating a Random Excitation Spectral Control (RESC) information element as a part of the comfort noise parameters, the RESC information element being used by a decoder in the base station for improving a spectral content of generated comfort noise so as to more closely match actual background noise at the mobile station.

9. A method for transmitting comfort noise (CN) parameters in a digital mobile station that operates in a discontinuous transmission (DTX) mode, comprising the steps of:

generating a comfort noise parameters message in response to a voice activity detector detecting an absence of speech; and

transmitting the comfort noise parameters message by concatenating the comfort noise parameters message with another message.

10. A method as in

claim 9

, wherein the another message is comprised of a neighbor channel measurement results message.

11. A method as in

claim 9

, wherein the another message is transmitted over a Fast Associated Control Channel (FACCH).

12. A method as in

claim 9

, wherein the another message is transmitted at one second intervals.

13. A method as set forth in

claim 9

, and including a step of generating a Random Excitation Spectral Control (RESC) information element as a part of the comfort noise parameters message, the RESC information element being used for improving a spectral content of generated comfort noise.

14. A mobile station operative with a base station, said mobile station comprising:

a transmitter;

an input speech transducer;

a voice activity detection (VAD) function coupled to said speech transducer; and

a controller having an input coupled to an output of said VAD function, to an output of said speech transducer, and to an input of said transmitter, said controller being responsive to said VAD function indicating an absence of user speech for initiating a Discontinuous Transmission (DTX) mode of operation and for transmitting at least one comfort noise (CN) block, the comfort noise block being comprised of a hangover period following a detected absence of speech and comfort noise parameters, said controller being operative for transmitting the comfort noise parameters message by concatenating the comfort noise parameters message with another message transmitted over a control channel.

15. A mobile station as in

claim 14

, wherein the control message is comprised of a neighbor channel measurement results message.

16. A method for transmitting comfort noise (CN) parameters in a digital mobile station that operates in a discontinuous transmission (DTX) mode, comprising the steps of:

generating a comfort noise parameters message in response to a voice activity detector detecting an absence of speech; and

transmitting the comfort noise parameters message over a traffic channel using Digital Control Channel (DCCH) channel coding and intraslot interleaving, thereby enabling the comfort noise parameters message to be sent in one time slot.

17. A method as set forth in

claim 16

, and including a step of generating a Random Excitation Spectral Control (RESC) information element as a part of the comfort noise parameters message, the RESC information element being used for improving a spectral content of generated comfort noise.