APPARATUS AND METHOD FOR ADAPTING A DIGITAL RADIOTELEPHONE SYSTEM TO INCREASED SUBSCRIBER TRAFFIC

摘要

A digital radiotelephone system employs vocoders (401, 403) to convert between analog speech and a digital format suitable for transmission via radio. Under most circumstances, the highest data rate is selected for optimum audio quality. When the system occupancy exceeds a particular threshold, as detected at the fixed site of the system, some or all of the vocoders (401, 403) are instructed to switch to a lower data rate to provide for an increase in the number of communication channels. Further, a portable subscriber unit (103, 111, 113) may autonomously change its vocoder data rate depending upon the charge state of its battery.