Date Added: Jul 2010
Speech quality is an important measurement for performance evaluation in a wireless mobile communication system since voice is still the most used service on it. The speech quality evaluation in GSM system employing narrowband and wideband AMR codecs with Orthogonal Sub Channel (OSC) technique is addressed in this paper. OSC is a feature proposed in 3GPP GERAN to double circuit switched capacity in GSM networks. It has introduced two new channel modes, namely Double Full-Rate (DFR), and Double Half-Rate (DHR), which have doubled capacity when compared to legacy AMR channel modes.