Channel estimation for DS/CDMA systems with aperiodic spreading codes and multiple antennas

The problem of channel estimation for DS/CDMA systems employing aperiodic spreading codes and multiple transmit and receive antennas is considered. Several estimation algorithms are presented, with different degrees of computational complexity and required prior information. In particular, both the situations of centralized channel estimation for all the active users and decentralized channel estimation for only one user of interest are specifically considered.