Discontinuous transmission (DTX) controller system and method
AssigneeQUALCOMM Incorporated
InventorAnthony Mauro
Life of this patent
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Abstract
A method and apparatus for controlling a discontinuous transmission process. Audio information is digitized and provided to a vocoder. A voice activity level is determined from the digitized audio signal, and if voice activity is present, active vocoder frames are generated at a predetermined output rate. If voice activity is not detected, inactive vocoder frames are generated. During transitions between periods of speech activity and speech inactivity, transition frames are generated, the transition frames comprising background noise information.
Claims5
A method for controlling discontinuous transmissions, comprising the steps of:
- determining a voice activity level in a digitized audio signal;
- generating a control signal based on the level of voice activity detected;
- generating active vocoder frames at a predetermined rate in a transmitter if said control signal indicates a first level of speech activity;
- generating inactive vocoder frames if said control signal indicates a second level of speech activity;
- and
- generating transition frames if said control signal indicates a transition from said first level to said second level, said transition frames comprising background noise information.
A method for controlling discontinuous transmissions, comprising the steps of:
- generating data frames at a receiver;
- storing said data frames in a queue;
- providing at least one of said data frames from said queue to a decryption module if available in said queue;
- providing a state vector to said decryption module, said state vector incremented at a predetermined rate;
- generating a codebook from said decryption module, using at least said state vector, said codebook for decrypting at least one of said data frames;
- and
- disabling said state vector when said queue is in an underflow condition.
A discontinuous transmission controller, comprising:
- a vocoder for generating active vocoder frames from said digitized audio signal at a predetermined output rate if speech is present, for generating inactive vocoder frames during periods of speech inactivity, and for generating transition frames during transitions from speech activity to speech inactivity, said transition frames comprising background noise information.
Dependencies are inferred from the claim text.