Performance analysis of voice message service in CDMA cellular systems

In this paper, we propose and analyze a preemption based admission control policy for an integrated voice and voice message service (VMS) CDMA system. Granted with the priority, the performance of voice calls is not affected by VMS. A multicode scheme is used for VMS traffic to transmit on multiple spreading codes in parallel. The SIR constraints of voice and VMS calls are taken into account to identify the system capacity. By using a two-dimensional Markov model, the performance of the integrated system is evaluated. Under different system traffic loads, QoS-based system capacities are obtained and optimal coding schemes for VMS are specified. Finally, the effect of the VMS buffer size is discussed.