Subjective performance of modulation systems for mobile satellite

Details the subjective performance of various modulation schemes and speech processing techniques with application to the mobile satellite service. The comparison is based on a mean opinion score (MOS) assessment of voice quality with measurements drawn from a number of recent publications and laboratory measurements. Of particular interest is the performance of an analogue form of linear modulation (ACSSB) when compared with a digitised voice source used in conjunction with an appropriate data modulation system. It is found that for a given bandwidth/power budget, the linear analogue system will always outperform the digital equivalent for the present generation of voice coder technologies. The performance gain is most dramatic in a fading (Ricean) environment