Transmission quality of north American cellular, personal communications, and public switched telephone networks

摘要

Future long distance, and especially international calls, will involve an increasing number of multilink circuits of cellular, personal communications, mobile satellite, and public switched telephone network (PSTN) type of connections incorporating a variety of speech coding devices. In particular, the rapid growth of cellular communications has highlighted the need to characterize the quality of switched networks when cellular terminals are attached at their termination nodes. At the same time, the nonlinear nature of low-rate parametric speech coding has rendered questionable analytical methods for estimating end-to-end voice quality of interconnected telecommunications networks. Instead, quantification of transmission performance appears to require direct subjective evaluation of the pertinent conditions of interest. In this paper the quality of interconnected North American digital cellular and future microcellular terminals with 16 kbit/s and 32 kbit/s DCME/PCME-based switched and private telephone networks is quantified. From these assessments it can be concluded that cellular networks employing the TIA IS-54 8 kbits/s VSELP algorithm may meet the end-to-end transmission planning criteria when interconnected with the switched network.