A method of detecting at a base station whether a transmitted data frame from a mobile station, UE, is a discontinuous transmission, DTX, frame, comprising: generating, from a signal carrying the frame that is received by the base station receiver, a signal metric corresponding to the transmitted data frame in a decoding operation used to decode the data frame, extracting, in a pilot channel processor, a noise energy value from the transmitted data frame, determining a signal energy of the transmitted data frame based on the signal metric, and determining whether the transmitted data frame is a DTX frame using a calculated signal-to-noise ratio based on the determined signal energy and on the extracted noise energy value, wherein the method of detecting is characterised by generating the signal metric includes: generating soft symbols at the base station from a received signal carrying the transmitted data frame, and decoding the soft symbols in a turbo decoder to generate the signal metric to be used for DTX detection, wherein decoding includes: computing log-likelihood ratio, LLR, amplitudes for all systematic bits in the transmitted data frame, and determining a final turbo decoded Log-Likelihood Ratio, LLR, for each of the systematic bits in the data frame as the signal metric for DTX detection; inputting the signal metric into an accumulator of LLR amplitudes of all systematic bits only, over the entire data frame, wherein the signal energy of the transmitted data frame is determined as an energy value of the output of the accumulator. generating, from a signal carrying the frame that is received by the base station receiver, a signal metric corresponding to the transmitted data frame in a decoding operation used to decode the data frame, extracting, in a pilot channel processor, a noise energy value from the transmitted data frame, determining a signal energy of the transmitted data frame based on the signal metric, and determining whether the transmitted data frame is a DTX frame using a calculated signal-to-noise ratio based on the determined signal energy and on the extracted noise energy value, wherein the method of detecting is characterised by generating the signal metric includes: generating soft symbols at the base station from a received signal carrying the transmitted data frame, and decoding the soft symbols in a turbo decoder to generate the signal metric to be used for DTX detection, wherein decoding includes: computing log-likelihood ratio, LLR, amplitudes for all systematic bits in the transmitted data frame, and determining a final turbo decoded Log-Likelihood Ratio, LLR, for each of the systematic bits in the data frame as the signal metric for DTX detection; inputting the signal metric into an accumulator of LLR amplitudes of all systematic bits only, over the entire data frame, wherein the signal energy of the transmitted data frame is determined as an energy value of the output of the accumulator. generating soft symbols at the base station from a received signal carrying the transmitted data frame, and decoding the soft symbols in a turbo decoder to generate the signal metric to be used for DTX detection, wherein decoding includes: computing log-likelihood ratio, LLR, amplitudes for all systematic bits in the transmitted data frame, and determining a final turbo decoded Log-Likelihood Ratio, LLR, for each of the systematic bits in the data frame as the signal metric for DTX detection; inputting the signal metric into an accumulator of LLR amplitudes of all systematic bits only, over the entire data frame, wherein the signal energy of the transmitted data frame is determined as an energy value of the output of the accumulator. computing log-likelihood ratio, LLR, amplitudes for all systematic bits in the transmitted data frame, and determining a final turbo decoded Log-Likelihood Ratio, LLR, for each of the systematic bits in the data frame as the signal metric for DTX detection; inputting the signal metric into an accumulator of LLR amplitudes of all systematic bits only, over the entire data frame, wherein the signal energy of the transmitted data frame is determined as an energy value of the output of the accumulator.