System and method for robustly detecting voice and DTX modes

A method of determining whether a receiver in a DTX-capable digital speech communications system having unique frames for demarking the beginning of DTX mode, demarking the end of DTX mode, and containing comfort noise frames should remain in inactive (DTX) mode or switch to active (non-DTX) mode, the method comprising:

• receiving a frame in inactive (DTX) mode;
• determining if the received frame is a comfort noise frame and processing accordingly;
• otherwise,
• determining if the received frame includes a marker signifying the end of DTX and switching to active (non-DTX) mode;
• otherwise,
• determining if the received frame is a voice frame, and if so, switching to active (non-DTX) mode, otherwise classifying the received frame as a NO_DATA frame and remaining in inactive (DTX) mode.

A system for determining whether a receiver in a DTX-capable digital speech communications system having unique frames for demarking the beginning of DTX mode, demarking the end of DTX mode, and containing comfort noise frames should remain in active (non-DTX) mode or switch to inactive (DTX) mode, the system comprising:

• means for receiving a frame in active (non-DTX) mode;
• means for determining if the received frame includes a marker signifying the beginning of DTX and processing accordingly by switching to inactive (DTX) mode;
• otherwise,
• means for determining if the received frame is a comfort noise frame and processing accordingly by switching to inactive (DTX) mode;
• otherwise,
• means for processing the received frame as a voice frame in active (non-DTX) mode.

A system for determining whether a receiver in a DTX-capable digital speech communications system having unique frames for demarking the beginning of DTX mode, demarking the end of DTX mode, and containing comfort noise frames should remain in inactive (DTX) mode or switch to active (non-DTX) mode, the system comprising:

• means for receiving a frame in inactive (DTX) mode;
• means for determining if the received frame is a comfort noise frame and processing accordingly;
• otherwise,
• means for determining if the received frame includes a marker signifying the end of DTX and switching to active (non-DTX) mode;
• otherwise,
• means for determining if the received frame is a voice frame, and if so, switching to active (non-DTX) mode, otherwise classifying the received frame as a NO_DATA frame and remaining in inactive (DTX) mode.

A method of determining whether an AMR enabled receiver in active (non-DTX) mode should remain in active (non-DTX) mode or switch to inactive (DTX) mode, the method comprising:

• performing a SID_FIRST marker comparison on the received AMR frame comprising:
• comparing bits in the SID_FIRST marker fields of the received AMR frame against a SID_FIRST marker;
• determining whether the results of the SID_FIRST marker comparison exceed a SID_FIRST threshold, and if so, processing the received AMR frame as a SID_FIRST frame and entering inactive (DTX) mode;
• otherwise,
• performing a SID_UPDATE marker comparison on the received AMR frame comprising:
• comparing bits in the SID_UPDATE marker field of the received AMR frame against a SID_UPDATE marker;
• determining whether the results of the SID_UPDATE marker comparison exceed a SID_UPDATE threshold, and if so, processing the received AMR frame as a SID_UPDATE frame and entering inactive (DTX) mode;
• otherwise,
• processing the received AMR frame as a voice frame in active (non-DTX) mode.

A method of determining whether an AMR enabled receiver in inactive (DTX) mode should remain in inactive (DTX) mode or switch to active (non-DTX) mode, the method comprising:

• receiving an AMR frame in inactive (DTX) mode;
• performing an ONSET frame comparison on the received AMR frame comprising:
• comparing the received AMR frame against a set of possible ONSET frames;
• determining whether the results of ONSET frame comparison exceed a threshold, and if so, processing the received AMR frame as an ONSET frame and switching to active (non-DTX) mode;
• otherwise,
• performing a SID_UPDATE marker comparison on the received AMR frame comprising:
• comparing those bits in the SID_UPDATE marker field of the received AMR frame against a SID_UPDATE marker;
• determining whether the results of the SID_UPDATE marker comparison exceed a threshold, and if so, processing the received AMR frame as a SID_UPDATE frame and remaining in inactive (DTX) mode;
• otherwise,
• determining whether the received AMR frame is a voice frame, and if so, switching to active (non-DTX) mode, otherwise classifying the received AMR frame as a NO_DATA frame and remaining in inactive (DTX) mode.

A system for determining whether an AMR enabled receiver in active (non-DTX) mode should remain in active (non-DTX) mode or switch to inactive (DTX) mode, the system comprising:

• means for performing a SID_FIRST marker comparison on the received AMR frame comprising:
• means for comparing bits in the SID_FIRST marker fields of the received AMR frame against a SID_FIRST marker;
• means for determining whether the results of the SID_FIRST marker comparison exceed a SID_FIRST threshold, and if so, processing the received AMR frame as a SID_FIRST frame and entering inactive (DTX) mode;
• otherwise,
• means for performing a SID_UPDATE marker comparison on the received AMR frame comprising:
• means for comparing bits in the SID_UPDATE marker field of the received AMR frame against a SID_UPDATE marker;
• means for determining whether the results of the SID_UPDATE marker comparison exceed a SID_UPDATE threshold, and if so, processing the received AMR frame as a SID_UPDATE frame and entering inactive (DTX) mode;
• otherwise,
• means for processing the received AMR frame as a voice frame in active (non-DTX) mode.

A system for determining whether an AMR enabled receiver in inactive (DTX) mode should remain in inactive (DTX) mode or switch to active (non-DTX) mode, the system comprising:

• means for receiving an AMR frame in inactive (DTX) mode;
• means for performing an ONSET frame comparison on the received AMR frame comprising:
• means for comparing the received AMR frame against a set of possible ONSET frames;
• means for determining whether the results of ONSET frame comparison exceed a threshold, and if so, processing the received AMR frame as an ONSET frame and switching to active (non-DTX) mode;
• otherwise,
• means for performing a SID_UPDATE marker comparison on the received AMR frame comprising:
• means for comparing those bits in the SID_UPDATE marker field of the received AMR frame against a SID_UPDATE marker;
• means for determining whether the results of the SID_UPDATE marker comparison exceed a threshold, and if so, processing the received AMR frame as a SID_UPDATE frame and remaining in inactive (DTX) mode;
• otherwise,
• means for determining whether the received AMR frame is a voice frame, and if so, switching to active (non-DTX) mode, otherwise classifying the received AMR frame as a NO_DATA frame and remaining in inactive (DTX) mode.