Code Division Multiple Access (CDMA) and Orthogonal Frequency Division Multiplexing (OFDM) and are the technology used in all third generation cellular communications networks, and it is a promising candidate for the definition of fourth generation standards. This paper refers to channel estimation based on time-domain channel statistics. Using a general model for Stanford University Interim SUI channels model, the aim of the paper is to find out the most suitable channel estimation algorithms for the existing CDMA and modified the bit error rate for this system. Starting with the analysis of channel estimation algorithms, we present the Minimum Mean Square Error (MMSE (and Least Square (LS (estimators and compromising between performances ...