A model for evaluating the performance of CDMA cellular systems

We present a queueing model to evaluate the performance of CDMA reverse link in a multiple cell environment. Since CDMA capacity is interference limited, both the communication quality of ongoing calls and the admission condition of new arriving calls for each cell depend on the time-varying signal-to-interference ratio (SIR). We use a quasi-birth-and-death process to capture the variation of traffic loads in cells. After obtaining the stationary distribution of the system, we study some important performance indices such as the outage probability of existing calls, the blocking probability of new calls, the average carried traffic in a cell, and the dropping frequency of ongoing calls. Numerical results reveal the effects of system parameters on its performance.