IMPACT OF NETWORK ROUTING ON THE END-TO-END TRANSMISSION QUALITY OF CELLULAR AND PCS CONNECTIONS

Long-distance and especially international calls involve an increasing number of multilink circuits of cellular, personal communications, mo bile satellite, and public switched telephone network (PSTN)-type conn ections incorporating a variety of speech coding devices, In particula r, the rapid growth of cellular communications and the impeding emerge nce of personal communication systems (PCS's) has highlighted the need to characterize the quality of end-to-end connections when cellular a nd PCS terminals are connected over the PSTN. At the same time, the no nlinear nature of low-rate parametric speech coding has rendered unsui table known analytical methods for estimating end-to-end quality of in terconnected networks. Instead, quantification of transmission perform ance requires direct subjective evaluation of the pertinent connection s of interest. In this paper, the quality of North American, Japanese, and European digital cellular and PCS terminals is quantified when th ese are interconnected using 16-kb/s low-delay code-excited linear pre diction (LD-CELP) and 32-kb/s adaptive differential pulse code modulat ion (ADPCM) facilities. From these assessments, it can be concluded th at digital cellular networks may meet end-to-end transmission planning criteria when interconnected with the switched network as long as cal ls are terminated to a wired terminal.