One of the main factors that affects the performance of a Code Division Multiple Access (CDMA) system is the out of-cell interference. While the in-cell interference is controlled within each cell using a power control algorithm, the out of -cell
interference is not and can greatly impact network coverage and the total user capacity, so that CDMA capacity is an interference limited capacity. One design technique to reduce the effect of the out of-cell interference in cellular CDMA
systems is to use cells of different radii, hierarchically organized in overlapping layers, this is the multitier system. In This paper the user capacity on the reverse link direction of a certain two-tier CDMA system that consists of a small microcell
embedded in a larger macrocell, i.e. a two cell system is examined. The effect of the users' mobility on the call blocking and call dropping probabilities is examined depending on the system feasibility. The simulation results show that at different call arrival rates the system capacity is increased as compared with the previous work. The dominant parameters affecting the system performance are the users' velocity and the distance between the two cells.