Decision feedback equalization for MC-CDM with channel uncertainty

We address the problem of interference cancellation for MC-CDM when the channel is uncertain, i.e., not perfectly known. In contrast to the decision-directed schemes that iteratively improve a channel estimate, we study a simpler receiver that tries to allow for the uncertainty of a solely pilot-based estimate. For this, we first derive the optimal receiver for both OFDM and MC-CDM, which merges the two processing stages of channel estimation and data detection, and show that this receiver may be partitioned into a pilot-based channel estimator and a detector that incorporates the estimator´s error covariance matrix. Such a decomposition suggests an error model on the basis of deriving a block decision feedback equalizer (BDFE) which utilizes the estimator´s error covariance as a reliability information. Simulation results demonstrate the performance of the error-aware BDFE.