Development of a test-bench for objective speech quality measurements under different simulated fading conditions

This paper presents a new test-bench developed by Telital S.p.A., in co-operation with the Electronics Department of the University of Trieste, in order to evaluate the quality of the speech coding and decoding algorithms for the newest generation of GSM terminals. A Data Acquisition System (DAS) has been implemented to obtain, in addition to subjective speech quality measurements (as usually in literature), also objective speech quality measurements. In the paper, some important features of GSM speech codecs are highlighted and summarised through the analysis of the above mentioned objective quality measurements. These measurements have been performed on the Telital GSM terminal in different simulated fading conditions. This allows one to test not only the efficiency of the particular channel "coding+interleaving" scheme employed for different carrier-to-interference (C/I) conditions, but also the efficiency of such scheme for different fading rates.