The influence of discontinuous transmission on equal statistics in GSM

Discontinuous transmission (DTX) is a feature which has been reported to give about 2.5 dB gain in C/I performance. However in real life, network operators, who switch on DTX, often experience a loss in performance. They measure the performance by the RXQUAL distribution. RXQUAL is a quality parameter used in GSM, which is directly related to the estimated BER before decoding. In the non-DTX mode the estimated BER is based on 100 bursts within 0.48 sec, while in the DTX mode the BER estimate is based on only 12 bursts within the same period. One method of estimation is the BER, and its inaccuracies, is studied in this paper. It is also explained why the quality in a network, where DTX is turned on, seems to decrease. Real life measurements and simulation results are shown.