Capacity of channel hopping channel stream on cellular digital packet data (CDPD)

Because voice cellular systems must maintain low blocking probabilities, almost 20% of cellular channel capacity is unused, even during the busy hour. In an attempt to capture some of this unused capacity, CDPD hops between idle channels, working independently of the voice base station and the cellular switch. On a 54 channel base station with 2% blocking probability, a CDPD data channel can achieve almost 98% availability without increasing the blocking probability to voice users. For the popular “least idle” voice channel assignment algorithm, the hopping channel stream will dwell on a channel for an average of 14 seconds and will hop about 290 times per busy hour. A hopping CDPD channel stream adds average co-channel interference that would not be present otherwise. For a typical base station, the co-channel interference introduced by a single hopping channel stream is only 0.1 dB and results in a loss of geographical coverage of about 0.3%. Because the CDPD base station must monitor the frequency spectrum in real time, the demands on the radio frequency front-end and the signal processing firmware are severe. A wideband receiver offers performance improvements over a narrowband receiver