Power control analysis of Gaussian approximated WCDMA system under Rayleigh fading channel

Wideband Code Division Multiple Access (WCDMA) is an air interface standard specially designed for third generation (3G) mobile networks to provide low data rate voice services to high data rate multimedia services. But different types of multipath fading, multi-access and co-channel interferences put a limit on overall system performance. The mechanism of power control provides a best alternative to enhance the system performance. In this paper, the behavior of WCDMA system is analyzed by using Gaussian Approximation (GA) technique in which interference and channel noise in the system are generated by the approximations of mean and variance of interferer power. The various power control scenarios have been used to analyze the performance of Gaussian approximated WCDMA system. System performance with the severer effect of Rayleigh fading has also been analyzed for perfect power control based conventional and rake receivers. Simulation results are obtained for Signal to Interference Noise ratio (SIR) verses number of users and Bit Error Rate (BER) verses number of users at different power control scenarios with different system processing gain and different number of interfering cells. Results show that WCDMA system performance improves with perfect power control mechanism, at high processing gain with less number of interfering cells. It is also shown that rake receiver has much better performance than conventional receiver at different processing gain, different number of interfering cells.