Parallel interference cancellation with different linear equalisation and Rake receiver for the downlink MC-CDMA systems

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. MC-CDMA systems transmitting over multipath channels suffer from inter-symbol interference (ISI) and multiple access interference (MAI). Recently, MC-CDMA with equalisation has attracted much attention for its ability to obtain an excellent performance even in strong frequency-selective fading channels. In this study, the proposed architecture uses the minimum mean-square error (MMSE) with parallel interference cancellation (PIC) for downlink MC-CDMA system and compared with another system based on the rake receiver with PIC for downlink MC-CDMA system. A comparison between such architectures is presented. The effect of the tentative decision functions and the effect of the loading users on the performance of the two proposed receivers are discussed and presented in this study. Simulation results show that the combination of tentative decisions with PIC and equalisation provides an efficient solution to suppress the MAI and ISI in downlink MC-CDMA systems over frequency-selective fading channels.