The University of British Columbia

Cellular digital packet data (CDPD) is a secondary packet-switched data service which uses radio channels from advanced mobile phone standard (AMPS) cellular networks. The CDPD service is completely invisible to the AMPS service which maintains priority. A large portion of the capacity of the AMPS system goes unused due to the necessity of providing low blockage rates to its customers. This unused capacity can be used for packet data transmissions which yield to voice traffic when necessary. The length of time that a CDPD transmission can occupy a channel is greatly influenced by the channel assignment strategies of both the AMPS and the CDPD systems. This paper investigates these channel assignment strategies and their effect-on the CDPD channel holding times. These times are then compared to the optimum channel holding time attainable when the CDPD and AMPS networks use the cooperative strategy during which they communicate with each other. It is shown that if the right strategy is chosen, channel holding times equal to those of the cooperative case can be attained without the need of communication between the two systems