Method and apparatus for controlling the use of discontinuous transmission in a cellular telephone

• US 5,737,695 A
• Filed: 12/21/1996
• Issued: 04/07/1998
• Est. Priority Date: 12/21/1996
• Status: Expired due to Term

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Wahlstrom, Peter, Lagerqvist, Tomas
• Primary Examiner(s): Eisenzopf, Reinhard J.
• Assistant Examiner(s): TO, DORIS HA
• Application Number:
  US08/781,887
• Time in Patent Office: 472 Days
• Field of Search: 455/403, 455/422, 455/100, 455/434, 455/436, 455/101, 455/455, 455/105, 455/517, 455/114-115, 455/524, 455/117, 455/63, 455/67.1, 455/67.3, 455/68-70, 455/73 , 455/78, 455/79-80, 455/82, 455/83-84, 455/88, 455/550, 455/121, 455/561, 455/563, 455/575, 455/226.1, 455/226.2, 455/226.3, 395/2.35, 395/2.36, 395/2.37, 395/2.42, 379/406, 379/410, 381/110, 381/94.1-94.3, 370/443, 370/442, 370/435, 370/252, 370/294, 370/331, 370/321, 370/337, 370/347
• US Class Current: 455/79
• CPC Class Codes: G10L 19/012 Comfort noise or silence coding

Abstract

A method and apparatus for controlling the use of discontinuous transmission in a cellular telephone. The preferred embodiment of the present invention includes a voice activity detector for detecting the presence or absence of speech and an energy detector for measuring the energy level of sound input to a microphone of a cellular telephone during the absence of speech. The present invention also includes a comparator for comparing the measured noise energy level against a threshold value. The determination as to the presence or absence of speech and the output of the comparator are provided to a controller. The controller enables discontinuous transmission when the energy level detected during the absence of speech is less than or equal to the threshold value and disables discontinuous transmission when the measured energy level exceeds the threshold value.

Claims

1. A method for controlling the use of discontinuous transmission in a cellular telephone comprising the steps of:

detecting the presence or absence of speech input to a microphone of the cellular telephone;

measuring an energy level of sound input to the microphone of the cellular telephone when speech is absent;

comparing the measured energy level against a threshold value, the threshold value representing a maximum energy level of background noise allowable for use of discontinuous transmission;

enabling discontinuous transmission when the comparison indicates that the measured energy level is at or below the threshold value;

otherwise

disabling discontinuous transmission when the comparison indicates that the measured energy level is greater than the threshold value.

2. The method of claim 1, wherein the steps of detecting, measuring, comparing, enabling, and disabling are preformed by the cellular telephone.

3. A method for controlling the use of discontinuous transmission in a cellular telephone which communicates using time division multiple access, comprising the steps of:

detecting the presence or absence of speech input to a microphone of the cellular telephone during each time division multiple access frame;

measuring an energy level of sound input to the microphone of the cellular telephone during each time division multiple access frame when speech is absent;

comparing the measured energy level against a threshold value, the threshold value representing a maximum energy level of background noise allowable for use of discontinuous transmission;

enabling discontinuous transmission during frames when the comparison indicates that the measured energy level is at or below the threshold value;

otherwise

disabling discontinuous transmission during frames when the comparison indicates that the measured energy level is greater than the threshold value.

4. The method of claim 3, wherein the steps of detecting, measuring, comparing, enabling, and disabling are preformed by the cellular telephone.

5. An apparatus for controlling the use of discontinuous transmission in a cellular telephone comprising:

a voice activity detector, positioned within the cellular telephone, for detecting the presence or absence of speech input to a microphone of the cellular telephone;

an energy detector, positioned within the cellular telephone, for measuring the energy level of sound input to the microphone of the cellular telephone when the voice activity detector indicates that speech is absent;

a comparator, positioned within the cellular telephone, for comparing the energy level measured by the energy detector against a threshold value, the threshold value representing a maximum energy level of background noise allowable for use of discontinuous transmission; and

a controller, positioned within the cellular telephone, for enabling discontinuous transmission when the energy level is at or below the threshold value and for disabling discontinuous transmission when the energy level is above the threshold value.

6. A method for controlling the use of discontinuous transmission in a cellular telephone comprising the steps of:

disabling, by a base station, discontinuous transmission following a cellular telephone call set-up or hand-off;

detecting, by a base station, the presence or absence of speech input to a microphone of the cellular telephone, the microphone output having been transmitted to the base station;

measuring, by the base station, an energy level of sound input to the microphone of the cellular telephone when speech is absent, the sound having been transmitted to the base station;

comparing, by the base station, the measured energy level against a threshold value, the threshold value representing a maximum energy level of background noise allowable for use of discontinuous transmission;

enabling, by the base station, discontinuous transmission when the comparison indicates that the measured energy level is at or below the threshold value;

otherwise disabling, by the base station, discontinuous transmission when the comparison indicates that the measured energy level is greater than the threshold value.

7. A method for controlling the use of discontinuous transmission in a cellular telephone which communicates using time division multiple access, comprising the steps of:

disabling, by a base station, discontinuous transmission following a cellular telephone call set-up or hand-off;

detecting, by the base station, the presence or absence of speech input to a microphone of the cellular telephone during each time division multiple access frame, the microphone input having been transmitted to the base station;

measuring, by the base station, an energy level of sound input to the microphone of the cellular telephone during each time division multiple access frame when speech is absent, the sound having been transmitted to the base station;

comparing, by the base station, the measured energy level against a threshold value, the threshold value representing a maximum energy level of background noise allowable for use of discontinuous transmission;

enabling, by the base station, discontinuous transmission during frames when the comparison indicates that the measured energy level is at or below the threshold value;

otherwise

disabling, by the base station, discontinuous transmission during frames when the comparison indicates that the measured energy level is greater than the threshold value.

8. An apparatus for controlling the use of discontinuous transmission in a cellular telephone comprising:

a voice activity detector, positioned within a base station, for detecting the presence or absence of speech input to a microphone of the cellular telephone, the microphone input having been transmitted to the base station;

an energy detector, positioned within the base station, for measuring the energy level of sound input to the microphone of the cellular telephone when speech is absent, the sound having been transmitted to the base station;

a comparator, positioned within the base station, for comparing the energy level measured by the energy detector against a threshold value, the threshold value representing a maximum energy level of background noise allowable for use of discontinuous transmission;

a controller, positioned within the base station, for transmitting a command to the cellular telephone to enable discontinuous transmission when the energy level is at or below the threshold value, the controller further for transmitting a command to the cellular telephone to disable discontinuous transmission when the energy level is above the threshold value; and

a controller, positioned within the cellular telephone, for implementing the commands transmitted from the controller positioned within the base station.