Trading CDPD availability and voice blocking probability in cellular networks

Abstract

Cellular digital packet data offers mobile users access to a low-cost, ubiquitous, wireless data network. CDPD can be overlaid on existing AMPS analog cellular systems and share their infrastructure equipment on a noninterfering basis. Since CDPD utilizes the idle radio resources of AMPS, it is important to ensure that the normal AMPS activities are not affected by CDPD. Several timers and system parameters are defined in CDPD for this purpose. This article investigates how these timers and parameters affect the performance of AMPS/CDPD systems. Our study provides guidelines for the selection of input parameters to aid CDPD network planning. Specifically, we study the trade-off between CDPD availability and voice blocking probability. In this article, CDPD availability is defined as the proportion of time that the RF channels can be used to transmit CDPD data. We observe that selecting too large values for CDPD dwell time and the maximum number of CDPD channel streams will degrade the voice blocking probability without improving CDPD availability. On the other hand, selecting a too large value for the CDPD layoff time will degrade CDPD availability without improving voice blocking probability.

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“…(Modified) versions of the Round Robin and Earliest Deadline First disciplines are generally considered most promising, although the latter is also expected to be rather complex from an implementation viewpoint [Pang et al,29]. Integrated voice (GSM) / data (GPRS) networks with a dynamic radio resource allocation algorithm have been studied via simulation by Bianchi et al [3], Chuang et al [10] and Kennedy and Litjens [21] where the grade (voice) and quality of service (data) is determined as a function of the voice and data traffic loads, as well as the number of dedicated data traffic channels. Kennedy and Litjens [21] illustrate the dependency of the data call delays and the present number of (prioritised) voice calls by means of a typical simulation trace.…”