Cramer-Rao Bound for blind channel estimation in multi-carrier CDMA systems

In this paper we present a study of the effect of considering codes larger than the spreading gain when estimating the channel in a MultiCarrier Code Division Multiple Accès (MC-CDMA) system. In order to perform this study we calculate the Cramer-Rao Bound (CRB) of channel estimators for a MC-CDMA system. CRB gives a lower bound on the error covariance matrix for a parameter vector (in our case, the channel impulse response vector) [5], and it gives a benchmark against which algorithms performance can be compared.