The Multi-Carrier Code Division Multiple Access (MC-CDMA) is becoming a very attractive multiple access technique for high-rate data transmission in the future wireless communication systems. The advantage of MC-CDMA systems that is work in frequency domain. Recently, MC-CDMA with any equalization scheme has attracted much attention for its ability to obtain an excellent performance even in strong frequency selective fading channels. In this paper, the two proposed architecture of the downlink MC-CDMA is based on the regularized zero forcing equalizer (RZF) with parallel interference cancellation (PIC) RZF-PIC) and the rake receiver with parallel interference cancellation (PIC) (RAKE-PIC) to suffer from the intersymbol interference (ISI) and multiple access interference (MAI). Two schemes are implemented in frequency domain. The effects of the tentative decision functions, the user loading on the performance of the proposed receivers architecture, and the number of cancelled users are discussed in this paper. Simulation results show the advantage
of the RZF equalizer result over rake receiver and show that the combination of PIC and equalization provides an efficient solution to suppress the MAI and ISI in downlink MCCDMA systems over frequency selective fading channels.