In this paper, we propose a theoretical method in order to estimate the forward link outage probability and user capacity of a cellular system which are based on IS 95 CDMA standard, especialy impact of power control strategy and voice activity monitoring in the system under long term fading effects, in which the light and heavy fadings are considered. According to the numerical results obtained in this paper, the power control strategy leads to approximately the threefold user capacity in contrast to the situation without power control strategy. The reults are compared with Interference to Signal Ratio( ISR ) driven power control scheme [6][9] which can be used only for simulation of the system. The power control strategy not only improves the desired signal to the interference ratio in the reference users receiver, but also offers uniform service to the user wherever it is located in the cell. In this paper, we propose a theoretical method in order to estimate the forward link outage probability and user capacity of a cellular system which are based on IS 95 CDMA standard, especialy impact of power control strategy and voice activity monitoring in the system under long term fading effects, in which the light results in this paper, the power control strategy leads to the threefold user capacity in contrast to the situation without power control strategy. to Signal Ratio (ISR) driven power control scheme [6] [9] which can be used only for simulation of the system. The power control strategy only only improves the desired signal to the interference ratio in the reference user’s receiver, but also offers uniform service to the user wherever it is located in the cell.