Digital Mobile Radio Systems require low bit rate speech codecs maintaining a high quality In spite of bad transmission conditions. In Europe, work Is under way for the standardization of a digital mobile radio system at 900 MHz (GSM). Until now, a 13 Kbit/s speech codec based on a Regular-Pulse Excitation Long-Term Prediction (RPE-LTP)  algorithm and a protection scheme for voice traffic channels at gross bit rate of 22. 8 Kbit/s have been standardized by ETSI/GSM. Recommendations leave room for Improvements at various levels of the digital signal processing. The optimization of the subjective speech quality required the set-up of a test bed allowing a continuous check and evaluation of the adopted algorithms. This paper focus on the test arrangements at Italtel Labs for voice quality assessment and describes our approach In the optimization of the GSM receiver. Keywords: Digital Mobile Radio System; GSM; Italtel Labs; Full Rate system; Half Rate system; Test bed; Enhanced BFI
Bibliographic reference. Rosina, G. / Agostino, M. Sant' / Turco, E. / Vetrano, L. (1991): "Testing and quality enhancement of the GSM full rate voice channel", In EUROSPEECH-1991, 611-614.