On the Performance of MC-CDMA Systems with TORC Detection and Channel Estimation Error

In this work the performances of a multi-carrier code division multiple access (MC-CDMA) system are analytically evaluated when a threshold orthogonality restoring combining (TORC) detector is adopted at the receiver of the downlink and not perfect channel state information (CSI) is provided. The analytical framework here proposed allows the derivation of the bit error probability (BEP) expression and its dependence on the number of sub-carriers, the number of active users, the mean signal-to-noise ratio (SNR) averaged over fast fading, the threshold of the detector and the variance of the channel estimation errors. Moreover, the dependence of the threshold on the channel estimation error is evaluated, providing the optimum value of the threshold minimizing the BEP as a function of the channel estimation error variance.