Prediction of time-varying multipath fading channel for pre-equalization of the signal in uplink mobile MC-CDMA communications

MC-CDMA is hard to be employed for uplink transmission because signals of users propagate through the different multi-path fading channels and lose orthogonality. To solve this problem pre-equalization must be used by users employing the downlink channel response. The pre-equalization is effective for stationary channels with fixed users, but not for time-varying channels, since there is a big difference between downlink and uplink channel responses. For time-varying channels users should predict the uplink response from downlink observation. This paper proposes a method for the prediction by means of the spectral decomposition of downlink response. Computer simulation results show that the proposed method provides accurate prediction for high mobility users during the whole uplink transmission