Abstract: A system and method of determining whether a receiver in active (non-DTX) mode should remain in active (non-DTX) mode or switch to inactive (DTX) mode and vice versa. For switching from non-DTX to DTX mode in a receiver, a received AMR frame is subjected to a SID_FIRST marker comparison. If the results of the SID_FIRST marker comparison exceed a SID_FIRST threshold, then the received AMR frame is processed as a SID_FIRST frame and the receiver is switched to DTX mode. Otherwise, the received AMR frame is subjected to a SID_UPDATE marker comparison. If the results of the SID_UPDATE marker comparison exceed a SID_UPDATE threshold, then the received AMR frame is processed as a SID_UPDATE frame and the receiver is switched to DTX mode. Otherwise, the received AMR frame is processed as a voice frame in non-DTX mode. For switching from DTX to non-DTX mode in a receiver, a received AMR frame in DTX mode is subjected to an ONSET frame comparison.

Abstract: A method by which a cellular phone (mobile station) operating in a multi-rate speech service environment and having a battery near its end of life may extend remaining talk time. The mobile station essentially reduces its transmit power settings while adjusting its codec mode to compensate for the reduction in transmission power. This trade-off extends the remaining talk-time available when the phone”s battery is nearing its end of life.

Abstract: A method of estimating initial channel quality in a receiver when allocated a new channel in order to select an optimal codec mode in a multi-rate service is disclosed. One implementation initially fills the filter state with the first received channel quality measurement. Another embodiment proportionally fills the entire filter state with the calculated channel quality measurements. Yet another embodiment uses the hysteresis and threshold parameters in conjunction with the initial codec mode to calculate an initial fill value for the filter state.

Abstract: A method of estimating initial channel quality in a receiver when allocated a new channel in order to select an optimal codec mode in a multi-rate service is disclosed. One implementation initially fills the filter state with the first received channel quality measurement. Another embodiment proportionally fills the entire filter state with the calculated channel quality measurements. Yet another embodiment uses the hysteresis and threshold parameters in conjunction with the initial codec mode to calculate an initial fill value for the filter state.

Abstract: A system and method of determining whether a receiver in active (non-DTX) mode should remain in active (non-DTX) mode or switch to inactive (DTX) mode and vice versa. For switching from non-DTX to DTX mode in a receiver, a received AMR frame is subjected to a SID_FIRST marker comparison. If the results of the SID_FIRST marker comparison exceed a SID_FIRST threshold, then the received AMR frame is processed as a SID_FIRST frame and the receiver is switched to DTX mode. Otherwise, the received AMR frame is subjected to a SID_UPDATE marker comparison. If the results of the SID_UPDATE marker comparison exceed a SID_UPDATE threshold, then the received AMR frame is processed as a SID_UPDATE frame and the receiver is switched to DTX mode. Otherwise, the received AMR frame is processed as a voice frame in non-DTX mode. For switching from DTX to non-DTX mode in a receiver, a received AMR frame in DTX mode is subjected to an ONSET frame comparison.

Abstract: Received signal quality (bit error rate) estimates for a communication channel are provided by a receiver apparatus which is connected to the communication channel and which includes a convolutional decoder providing an estimate of a transmitted data frame and an associated final decision metric. The bit error rate estimate is generated by a bit error rate estimation circuit which includes a memory containing values for mapping the final decision metric to a corresponding bit error rate estimate. The bit error rate estimate may be provided to a control node of the communication channel which may use the provided estimate to take a corrective action such as determining whether a handover to a different communication channel should be initiated based upon the bit error rate. The communication channel may be an allocated channel of a cellular radio communication network servicing a mobile terminal receiver apparatus with the control nodes being the base stations of the cellular network.

Abstract: A telecommunications system and method for improving the detection of speech and control signals within a telecommunications transmission, particularly, reducing the probability that the control signals and other non-speech transmission segments are interpreted as speech and played. Also, the system and method of the present invention is directed to techniques for reducing the probability that random noise during discontinuous transmission periods are interpreted as speech and played.